Note: Descriptions are shown in the official language in which they were submitted.
CA 02638922 2008-08-20
FILTER SCPA[tATION DEVICC
aACKcROUND OF TIIC INVENTION
Field of the [nvention
Tlie present invention relates to a filter separation cievice, in particularly
to a
filter separatioil clevice to separate and remove a magnetic floc whicli is
rnot collecteci ancl
removed by a magnetic separating device frotn raw ~vater by a cirum type
filter.
Description of the Relateci nrt
A magnetic separation devicc is conventionally known as an device to renlove
contalnitlants in raw water of sewage and industrial effluent. The magnetic
separation
device generates contaminants as a irnagnetic floe having a tnagnetized
characteristic by
adciing a flocculllllt at]d a nlagnetlc partlCle to the raw water. Tlleil, the
magnetic
separation device scparates and renioves the magnetic tloc from the raw water
by
adsorbing the magnetic floc to a magnetic disk whicli has a number of mabnets
provicled.
A solid-liquid separation clevice which has a magnetic separation device
btuilt
into is disclosed in Japanesc Patent Application Laid-Open No. l I10-244=124.
The
-nagnetic separation device has a plural of magnetic disks attached magnets
wllich zre
arranged in a predeterrtninetl clistance in an axis of rotation insicle of a
separation tank to
reniove the magnetic floe from the raw water by adsorbing tllc magnetic floc
to a
magnetic disk.
On the otlier hancl, a lilter separation device Nvllich removes large-size
dirt in the
raw vvater by using a drnm type filter is disclosed in Japanese Patent
Application
Laid-Open No. 2004-358343. When the raw water suppliecl into the cl--um type f
Iter
tlirotigh a feecl pipe, the large-size clirt is relnainecl insicle of the drum
type filter and
reinoved from the raw water. Also, a down streallls eild of a back flow
clealling Water
pipe is provided on the uppcr sicle of the dru-n type filter and a back I1ow
water withdraw
pan is provided inside of the drum type tilter at the opposeci position to the
down streanis
encl of the back tlow cleaning water pipe. 'Chese conf gurations makes it
possible to
flash away the large-size clirt attacliecl to the drum type lilter when the
back flovv
cleatling ~vater is [lashed front the clown streams encl of the back flow
cleaning water
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CA 02638922 2008-08-20
pipe. Then, the large-size dirt is withdrawn with the back flow cleaning water
into the
back flow water withdraw pan and removed frotn the drum type filter.
SUMMARY OF TFIE INVENTION
However, a pipe for supplying the raw water and a pipe which is connected to
the back flow water withdraw pan for withdrawing the back flow water are
provided at
different positions in the drum type filter in the filter separation device
disclosed in
Japanese Patent Application Laid-Open No. 2004-358343. Therefore, a piping
system
inside of the drum type filter is complicated, which makes the configuration
of the filter
separation device complicated. At the same time, it has disadvantage that
spots to eject
the pipes from the device need two watertight seals.
The present invention has been achieved in view of such circumstances. An
object of the present invention is to provide a filter separation device with
a simple
configuration by simplifying the conf guration of the piping system provided
in the drum
type filter.
To achieve the object above, according to a first aspect of the present
invention,
there is provided a filter separation device comprising: a main body formed in
a box
shape; a raw water supply pipe provided inside the main body in a horizontal
direction
and formed a number of discharge holes on a bottom surface to discharge a raw
water
which is supplied from the outside of the main body into the inside of the
main body; a
drum type filter rotatably attached to the raw water supply pipe to surround
the raw water
supply pipe and trap a trapped object in the raw water; a drive unit rotating
the drum type
filter; a trapped object discharge pipe which is inserted into the raw water
supply pipe,
having a trapped object intake at an open section formed on the upper surface
of the raw
water supply pipe and discharging the trapped object to the outside of the
main body; and
a water level control unit controlling a water level of the raw water in the
main body to
be lower than the trapped object intake of the trapped object discharge pipe,
wherein the
trapped object trapped by the drum type flter is dropped in the trapped object
intake of
the trapped object discharge pipe by being transferred above of the trapped
object intake
as the drum type filter rotates and discharged from the trapped object
discharge pipe via
the trapped object intake.
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According to the first aspect of the present invention, in a configuration of
a raw
water supply pipe and a trapped object discharge pipe provided in a drum type
filter, the
trapped object discharge pipe is inserted to the raw water supply pipe and the
a trapped
object intake is provided at the open section formed on the upper surface of
the raw
water supply pipe. In other words, the piping configuration of the raw water
supply
pipe and the trapped object discliarge pipe is a double layer which has the
raw water
supply pipe as an outer pipe and the trapped object discharge pipe as an
iniier pipe.
Thus, the number of pipes is reduced from the conventional two pipes system to
the one
pipe system so that the filter separation device having the simple structure
is produced
and the risk to decline of the quality of the treated water by leaks is
reduced because the
one pipe system requires only one spot to have a watertight seal.
In addition, when the number (the density) of the discharge holes is uniformly
formed, it causes problem that the raw water is mostly supplied from the
discharge holes
at the downstream due to fluid inertia. Therefore, it is preferable that the
number (the
density) of the discharge holes which are formed along the raw water supply
pipe is
decreased as going froni the upstream to the downstream of the raw water
supply pipe.
According to a second aspect of the present invention, there is provided the
filter
separation device according to the first aspect, wherein a bucket scooping the
trapped
object with rotation of the drum type filter is provided on the inner surface
of the drum
type filter.
In the second aspect of the present invention, a large size solid object (such
as a
large solid object which can not be flocculated and a living matter having
motility)of the
trapped object which is trapped by the drum type Iilter is efficiently scooped
by the
bucket and dropped to the trapped object intake of the trapped object
discharge pipe.
The large size solid object stays on the bottom of the dnun type filter which
can not be
brought up to the trapped object intake without the bucket. However, according
to the
present invention, is possible to prevent the deposition of the large size
solid object on
the drum type filter by using the bucket so that the drum type filter has
longer life.
On the other hand, the remained fine size magnetic floc F which is not
separated at the
magnetic separation device is moved upward as the druni type filter which is
clogged by
magnetic floc F rotates. Then the remained fine size magnetic floc F drops to
the intake
of the trapped object discharge pipe by spraying water.
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According to a third aspect of the present invention, there is provided the
filter
separation device according to any of the first and second aspects, wherein
the water
level control unit includes a water level sensor detecting a water level of
tlie raw water in
the drum type filter, a spray nozzle provided outside of the drum type filter
and carrying
away clogging of the drum type filter by spraying water to the drum type
filter, and a
control unit controlling an amount of water to spray from the spray nozzle
based on the
water level information from the water level sensor.
According to the filter separation device of the third aspect of the present
invention, when the water level in the drum type filter detected by the water
level sensor
exceeds the predetermined water level, the control unit recognizes that the
drum type
filter is clogged, and then the control unit controls amount of water to be
sprayed by the
spray nozzle. The drum type filter recovers from clogging and the water level
is back to
the preferable water level. The spray nozzle is preferably provided so that
the water is
sprayed to the intake of the trapped object discharge pipe, thereby the
trapped object
which causes the clogging of the filter is discharged with the water sprayed
from the
spray nozzle via the trapped object discharge pipe.
It is possible to prevent the drum type filter from being clogged with the
trapped
object as it grows by always spraying water from the spray nozzle but also the
operation
of spraying water from the spray nozzle can be ON/OFF according to the water
level
detected by the water level sensor. It is not preferable that the raw water is
discharged
from the intake of the trapped object discharge pipe when the water level
inside of the
drum type filter starts to increase. For this reason, the predetermined water
level which
is detected by the control unit is set to the water level which is little
lower than the intake
of the trapped object discharge pipe.
The water level of the raw water can be also lowered when the number of
rotations of the drum type tilter is increased because the cleaned filter
surface is fed one
after another. In other words, the number of rotations of the drum type filter
can be
controlled based on the detected water level.
According to a fourth aspect of the present invention, there is provided the
filter
separation device according to the third aspect, further cotnprising a
filtered water
circulation device which makes filtered water filtered by the drum type filter
to be
sprayed from the spray nozzle.
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According to the fourth aspect of the present invention, the filtered water
circulation device is provided with the drum type filter so that the filtered
water passed
through the cirum type filter is used for the spray nozzle. In this way, it is
possible to
conserve water for the spray nozzle.
According to a fifth aspect of the present invention, there is provided the
filter
separation device according to any one of the first to fourth aspects, wherein
a
flocculation device generating a magnetic floc containing a magnetic particle
by adding
the magnetic particle and a flocculant into the raw water containing a
contaminant and
agitating, and a magnetic separation device separating the magnetic floc
generated by the
flocculation device with a magnetic force are provided at the former stage of
the filter
separation device, and the filter separation device traps the magnetic floc
remained in the
raw water by the drum type filter.
The present invention according to the fifth aspect is related to an invention
of a
contaminated water purification system comprising the flocculation device and
the
magnetic separation device at the former stage of the drum type filter. Thus,
the
remained magnetic floc which is not separated by the magnetic separation
device is
trapped by the drum type filter. Then, the magnetic floc can be reliably
removed from
the raw water.
The filter separation device according to a sixth aspect of the present
invention
is the filter separation device according to the fifth aspect, wherein the
trapped object
discharge pipe is connected at the former stage of the flocculation device and
the
magnetic floc trapped by the druni type magnetic filter is returned to the
flocculation
device via the trapped object discliarge pipe.
According to the sixth aspect of the present invention, the trapped object
which
is trapped by the drum type filter such as a remained magnetic floc which is
not
separated by the magnetic separation device is returned to the flocculation
device,
thereby the magnetic particle contained in the magnetic floe can be reused as
a core for
the flocculation.
The filter separation device according to a seventh aspect of the present
invetition is the filter separatioii device according to any of the fifth and
sixth aspects,
wherein a fracture device is provided at the trapped object discharge pipe to
fracture the
magnetic floc.
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According to the invention of the seventh aspect, it is possible to prevent a
large
solid object from redeposit on the drum type filter by providing the fracture
device.
Also, the magnetic floc tends to work as a core of the flocculation when it is
fractured
into a fine state.
According to the filter separation device of the present invention, the piping
configuration of the raw water supply pipe and the trapped object discharge
pipe is a
double layer which has the raw water supply pipe as an outer pipe and the
trapped object
discharge pipe as an inner pipe. Thus, the number of pipes is reduced from the
conventional two pipes system to the one pipe system so that the filter
separation device
having the simple structure is produced.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a block diagram showing a contaminated water purification system
incorporating a filter separation device according to the embodiment of the
present
invention;
Fig. 2is a conceptual diagram of the contaminated water purification system;
Fig. 3 is a cross sectional view of the Flter separation device;
Fig. 4 is a perspective view showing a configuration of two pipes provided in
the filter separation device;
Fig. 5 is a cross sectional view of a drum type filter; and
Fig. 6 is an enlarged perspective view showing a bucket of the drum type
filter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the accompanying drawings, a detailed description will be given
below of preferred embodiments of a filter separation device of the present
invention.
Fig. 1 is a block diagram which explains a flow incorporating an embodiment of
the filter separation device 24 into a contaminated water purification system
10. Also,
Fig. 2 is a conceptual diagram of a flocculation clevice 14, a magnetic
separation device
20 and a ftlter separation device 24 which configure the contaminated water
purification
system 10.
As shown in Fig. 1, the raw water is conveyed to a high rate agitation tank
14A
of the flocculation device 14 by a raw water pump 12 in the contaminated water
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puriFcation system 10. A magnetic particle adding device 16 for adding a
magnetic
particle and a flocculant adding device 18 for adding a flocculant are
provided in a
midstream of a pipe for connecting the raw water pump 12 and the high rate
agitation
tank 14A and the magnetic particle and the flocculant are added to the raw
water flowing
inside of the pipe. As the inagnetic particle, an iron oxide black and like
can be
preferably used. As the flocculant, a hydrosoluble inorganic flocculant such
as
polyaluminum chloride, iron chloride and ferric sulfate can be preferably
used. It is
preferable that a strainer is provided at the former stage of adding the
magnetic particle
and flocculant to the raw water so that a relatively large dirt having the
size of a few
millimeters is removed.
An agitating blade 19A which rotates at high speed agitates the raw water, the
magnetic particle and the flocculant added to the raw water at a high rate in
the high rate
agitation tank 14A. In this way, a fine magnetic floc F(also referred as a
magnetic
micro floc) having the size of several tens of -nicrometer is produced in the
high rate
agitation tank 14A. It is preferably done with the circumferential speed of
rotating at
the edge of the agitating blade 19A about 1.0 to 2.0 m/sec. The magnetic
particle,
floating solid particles in the raw water, bacteria, plankton and like are
introduced into
the niicro floc.
The raw water including the magnetic micro floc is convey to a low rate
agitation tank 14B of the flocculation device 14. A polymer flocculant adding
device
21 for adding a polymer flocculant to the raw water is provided near by a
communicating
vessel 14C which communicates the high rate agitation tank 14A and the low
rate
agitation tank 14B so that the polymer flocculant is added to the raw water
flowing
through the communicating vessel 14C. As the polymer flocculant, an anionic
type and
a nonionic type can be preferably used.
The low rate agitation tank 14B has an agitating blade 19B which agitates the
magnetic micro floc and the polymer flocculant at low speed. A large size
magnetic
floc F having the size between several hundreds of micrometer to a few
millimeters is
produced by agitating the magnetic micro floc and the polymer flocculant at
low speed
with the agitating blade 19B. "Che low rate agitation tank 14B is composed of
plurality
of continuous stages which are multistage agitation vessels A), B) and C) as
shown in
Fig. 2. The rotate speeds of the agitating blades 19B are set to be slower as
going down
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the stream from the multistage agitation vessel A) to the multistage agitation
vessel C).
In tllis way, the magnetic floc F grows as it flows from the multistage
agitation vessel A)
at the upstream toward to the multistage agitation vessel C) at the
downstream, and it is
possible to prevent the grown magnetic floc F from being broken. For example,
as the
circumferential speeds of rotating the agitating blades 1913, it is preferably
set to about
0.5 to 1.0 misec at the multistage agitation vessel A), about 0.3 to 0.7 m/sec
at the
multistage agitation vessel B) and about 0.1 to 0.3 m/sec at the multistage
agitation
vessel C).
As shown in Fig. 2, it is preferably that the flocculation device 14 has the
integral structure including the high rate agitation tank 14A, the
communicating vessel
14C and the low rate agitation tank 14B. However, it is possible to configure
by
communicating the high rate agitation tank 14A, the communicating vessel 14C
and the
low rate agitation tank 14B with pipes.
In addition, the high rate agitation tank 14A, the communicating vessel 14C
and
the low rate agitation tank 14B of the flocculation device 14 are filled with
the raw water
by renioving the air. Therefore, the raw water can smoothly flow from the high
rate
agitation tank 14A to the low rate agitation tank 14B through the
communicating vessel
14C without ruffle at each tank 14A, 14B and 14C of the flocculation device 14
when the
contaminated water purification system 10 is loaded on a ship and the ship is
tossed on
the wave.
The raw water containing the magnetic floc F grown to the predetermined size
is
conveyed to the magnetic separation device 20. The magnetic separation device
performs adsorptive separation of the magnetic floc F from the raw water by
using
magnetic force. The magnetic separation device 20 adsorbs and separates
approximately 95% of the magnetic floc F in the raw water.
After the magnetic floc F removed from the raw water by the niagnetic
separation device 20, the percentage of water content of the magnetic floc F
is reduced to
80% by a dehydrator 25 such as a centrifuge, or a beltpress, or like. Then,
the magnetic
floc F is transported by a truck and disposed or treated at a landfill, or a
waste
incineration plant, or a compost plant.
On the other hand, a treated water treated in the magnetic separation device
20 is
conveyed to the filter separation device 24.
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In the filter separation device 24, the treated water (the raw water) is
supplied
the inside of the drum type Glter 26 through a raw water supply pipe 32. The
treated
water supplied to the inside of the dntm type f Iter 26 is filtered by flowing
out to the
outside of the drum type filter 26 and then a trapped object such as the
magnetic floc F
and like remained in the treated water is removed by the mesh filter of the
drum type
tilter 26 having the mesh size of about 25 m. Therefore, the raw water
containing the
contaminant sucli as dirt, floating solid particles, bacteria, plankton and
like is purified.
The trapped object such as the magnetic floc F attached to the inside of the
drutn
type tllter 26 drops on a hopper 34(a trapped object intake of an trapped
object outlet) in
the drum type filter 26 and the trapped object is discharged to the outside of
the filter
separation device 24 through a trapped object discharge pipe 36 by spraying
water from a
spray nozzle 28 which is provided above of the drum type filter 26. In this
embodiment,
the treated water purified by the drum type filter 26 is partially returned to
the spray
nozzle 28 by a circulation pump 29 (a filtered water circulating device) and
used as water
to spray from the spray nozzle 28. Also, the trapped object such as the
magnetic floc F
and like and the water sprayed froin the spray nozzle 28 are conveyed to the
former stage
of the raw water pump 12 by a pump 30 connected to the trapped object
discharge pipe
36.
The configuration and the characteristics of the filter separation device 24
are
described below.
Fig. 3 is the cross sectional view of the filter separation device 24, Fig. 4
is a
perspective view showing a configuration of two pipes provided in the filter
separation
device24, Fig. 5 is a cross sectional view of a drum type filter26, and Fig. 6
is an
enlarged perspective view showing a bucket64 of the drum type filter26.
As shown in Fig. 3, the filter separation device 24 are comprised of a main
body
38, the raw water supply pipe 32, the drum type filter 26, a motor 40 (refer
to Fig. 1: a
cirive part), the trapped objcet discharge pipe 36, a water level control unit
42 and like.
The main body 38 is formed in a box shape and the raw water sttpply pipe 32 is
provided as penetrating throtigh the main body 3 8 in the horizontal
direction. A nutnber
of discharge holes 33, 33... are provided on the bottom surface of the raw
water supply
pipe 32 in the axis of the raw water supply pipe 32 to discharge the raw water
which is
supplied from the magnetic separation device 20 in Fig. 1 into the main body
38.
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One end of the drum type filter 26 is rotatably attached to the raw water
supply
pipe 32 via a bearing 44 to surround the raw water supply pipe 32 as shown in
Fig. 3.
At the same time, a shaft 46 fixed to another end of the drum type filter 26
is rotatably
attached to the main body 38 via a bearing 48. A sprocket 50 are fixed to the
shaft 46
as shown in Fig. 1 arnd a chain 52 wound around the sprocket 50 is wound
around a
sprocket 54 at the side of the motor 40. Thus, the drum type filter 26 is
rotated by
chain-driven as the motor 40 driven.
The trapped object discharge pipe 36 is inserted to be fully inside of the raw
supply pipe 32 as shown in Fig. 3, 4 and the hopper 34 is projected from an
open section
32A having rectangular shape which is formed on the upper surface of the raw
water
supply pipe 32.
The water level control unit 42 as shown in Fig. 3 has a water level sensor 56
which detects the water level of the raw water in the drum type filter 26 from
the outside
of the main body 38 by using the raw water supply pipe 32, the spray nozzle 28
aforementioned, and a control unit 60 which controls amount of water to spray
from the
spray nozzle 28 by controlling opening of a magnetic valve 58 according to the
water
level information from the water level sensor 56. The control unit 60 controls
the water
level of the raw water in the main body 38 to be lower than the upper open
section of
hopper 34 of the trapped object discharge pipe 36.
By the filter separation device 24 such comprised, a trapped object 62
(including
the remaine(i magnetic floc F which is not separated at the magnetic
separation device
20) trapped by the drum type filter 26 drops when the trapped object moved to
above of
the hopper 34 of the trapped object discharge pipe 36 as the drum type filter
26 rotates.
Then, the trapped object is disciiarged from the trapped object discharge pipe
36 via
hopper 34.
Moreover, in the configuration of the raw water supply pipe 32 and the trapped
object discharge pipe 36 provicied in the drum type filter 26, the trapped
object discharge
pipe 36 is inserted to the raw water supply pipe 32 and the hopper 34 (a
trapped object
intake of an trapped object outlet) is provided at the open section 32A formed
on the
upper of the raw water supply pipe 32. In other words, the piping
configuration of the
raw water supply pipe 32 and the trapped object discharge pipe 36 is a double
layer
which has the raw water supply pipe 32 as an outer pipe and the trapped object
discharge
CA 02638922 2008-08-20
pipe 36 as an inner pipe. Thus, the number of pipes is reduced from the
conventional
two pipes system to the one pipe system so that the filter separation device
24 having the
simple structure is produced and the risk to decline of the quality of the
treated water by
leaks is reduced because the one pipe system requires only one spot to liave a
watertight
seal.
In addition, it is preferable that the number (the density) of the discharge
holes
33, 33... which are formed along the raw water supply pipe 32 is decreased as
going
from the upstream to the downstream of the raw water supply pipe 32. When the
number (tlie density) of the discharge holes 33, 33... is uniformly formed, it
causes
problem that the raw water is mostly supplied from the discharge holes 33,
33... at the
downstream due to fluid inertia.
Also, a plurality of buckets 64, 64...which scoop up a large size solid object
from a trapped object 62 by the rotation of the drum type filter 26 are
provided with
having the predetermined distance between each other in the circumferential
direction in
the inner surface of the drum type filter 26 as shown in Figs. 5 and 6. Thus,
the large
size solid object of the trapped object 62 which is trapped by the drum type
filter 26 is
efficiently scooped by the buckets 64, 64... and dropped to the hopper 34 of
the trapped
object discharge pipe 36 as the drum type filter 26 is rotated. It is possible
to prevent
the deposition of the large size solid object on the drum type filter 26 by
using the
buckets 64, 64... so that the drum type filter 26 has longer life.
Also, by the water level control unit 42 shown in Fig. 3, when the water level
in
the drum type filter 26 detected by the water level sensor 56 exceeds the
predetermined
water level, the control unit 60 recognizes that the drum type filter 26 is
clogged, and
then the control unit 60 controls the opening of the magnetic valve 58 to
supply a larger
amount of water to be sprayed by the spray nozzle 28. The drum type filter 26
recovers
from clogging and the water level is back to the preferable water level. The
spray
nozzle 28 is preferably provided so that the water is sprayed to the hopper 34
of the
trapped object discharge pipe 36, thereby the trapped object 62 which causes
the
clogging of the filter is discharged with the water sprayed from the spray
nozzle 28 via
the trapped object discharge pipe 36.
The water level of the raw water can be also lowered when the number of
rotations of the drum type filter 26 is increased because the cleaned filter
surface is fed
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one after another. In other words, the number of rotations of the drum type
filter 26 can
be controlled based on the detected water level. For eYample, the number of
rotations
of the drunl type filter 26 in the normal state is between 2 to 5 rpm.
It is possible to prevent the drum type filter 26 from being clogged with the
trapped object 62 as it grows by sprayiiig always water from the spray nozzle
28. On
the other hand, the operation of spraying water from the spray nozzle 28 can
be ON/OFF
according to the water level detected by the water level sensor 56. As shown
in Fig. 5,
it is not preferable that the raw water is discharged from hopper 34 of the
trapped object
discharge pipe 36 when the water level inside of the drum type filter 26
starts to increase.
For this reason, the predetermined water level which is detected by the
control unit 60 is
set to the water level which is little lower than the hopper 34 of the trapped
object
discharge pipe 36.
The filter separation device 24 of the present embodiment has the circulation
pump 29 (the filtered water circulating device) which makes the spray nozzle
28 to spray
the filtered water passed through the drum type filter 26. In this way, it is
possible to
conserve water for the spray nozzle 28 because the filtered water is used as
the water to
be sprayed from the spray nozzle 28 in the filter separation device 24.
Also, the filter separation device 24 is constructed so that the trapped
object
discharge pipe 36 of the drum type filter 26 is connected at the fonner stage
of the
flocculation device 14 and returns the trapped object 62 trapped by the drum
type filter
26 back to the flocculation device 14 via the trapped object discharge pipe
36.
Therefore, the trapped object 62 such as a remained magnetic particle which is
not
separated by the magnetic separation device 20 is returned to the flocculation
device 14
and the magnetic particle can be reused as a core for the flocculation.
Additionally, a pump 30 which has the ftinction to fracture the trapped object
62
is provided at the trapped object discharge pipe 36.
The pump 30 with the fracture function prevents the large size solid object
being
redeposited on the drum type filter 26 and fractures the trapped object 62
into a fine state
to tend to work as a core for the flocculation in the flocculatioti device 14.
12
