Note: Descriptions are shown in the official language in which they were submitted.
1059950
This invention relates to a wet drum type classifier,
and especially a drum-type sand classifier which has a cone-
~haped discharge chute that effectively discharges the clas~ified
sand and is e~ployed instead of the conventional belt conveyor.
Generally speaking, there are several methods of
separating solid particles into group~ which have the same
particle size range. An effective method i~ screening which is
performed by ~aking use of the difference in size of particles
to be classified but not of the difference in ~pecific gravity
of the particles. However, when classification of minute particles
which have a diameter of les~ than 0.1 mm is required, this
screening method i9 no longer useful.
Another effective method of separating particle~ into
groups of the same particle size range is called "classifying" .
Classifyine makes use of the settling velocity of solid particles
which are in a nuid body and the above velocitg varies corres-
ponding to the size as well as the specific gravity of the solid
particles. Thi5 clas~ifying generally consists of "wet clas~ify-
ing" which uses water as the fluid body and "dry classifying"
which uses air as the fluid body. Since the viscosity coefficient
of water i8 50 times greater than that of air, the settling speed
of solid particles also varies greatly depending on the fluid
body used. Accordingly the minimum size of a solid particles
which can be classified is around 10 ~ - 1 mm with "wet classify-
ing" while it is around 1 ~ - 1 mm with "dry ¢lassifying".
~he sand classifier of this invention make~ use of the
wet classifying method by which even the mud component can be
eliminated (classified) from muddy water which results in the
production of clear water.
The wet-type classifier generally comprises rake-type,
spiral-type and drum-type classifiers.
~he first two of the foregoing types of classifiers,
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lOS9950
however, are seldom used any longer since their classi~ying
efficiency is low and they cannot keep up with the demand for .
sand which i5 increasing remarkably these days. Therefore, the
drum-type classifier is predominately used.
According to the present invention, there is provided
a wet-type classifier comprising: a rotary drum which has a front
outlet at its front end and a rear outlet at its rear end, a
feeding means for feeding muddy water containing sand into the
drum, said feeding means being enclosed by the drum, disposed
concentrically within the drum and attached to the drum for rota-
tion with the drum, the feeding means having an inlet opening
ad~acent to the front outlet of the drum and an outlet
opening adjacent to the rear outlet of the drum,
a classifying means for causing sand which is contained in the
muddy water to settle onto the bottom of the drum and transferring
the settled sand towards the rear end of the drum, the classifying
means bei.ng fixedly secured to the interior surface of the drum and
covering substantially the entire length of the drum. A dischar-
ging means is fixedly secured to the rear end of the drum for ex-
pelling the transferred sand from the rear outlet of the drum com-
prising a plurality of paddles fixed to the interior of the drum,
each paddle having apertures for separating the water from the
sand before the sand is discharged from the classifier, the dis-
charching means being disposed at the rear end of the drum and a
cone-shaped member fixed to the inner ends of paddles for dischar-
ging the water-separated sand from said drum, the cone-shaped mem-
ber having an exterior inclined surface and disposed at the center
of the plurality of paddles, whereby substantiaily water-free
classified sand of a desired size range is produced by the rota-
tion of the drum with minimum wear on the classifier due to thefriction from the sand.
- 2
10599S0
The apparatus of this invention differs greatly
from the conventional apparatuses. The conventional apparatus
requires a belt conveyor which is inserted into the rotary drum
of the classifier and discharges the classified sand out of the
drum and is an indispensable element of the apparatus, while the
classifier of this invention has a unique discharge means which,
is integral with the rotary drum. The discharge system of the
invention is completely new and different from the conventional
system basically due to the aforementioned discharge means, which
results in a remarkable improvement of the classification efficiency,
a great increase in the amount of sand that is discharged without
sacrificing the compactness of the apparatus and a drastic decrease
of mechanical failures which are caused due to friction or corrosion
of the parts of the apparatus.
Since the conventional drum-type classifier
requires a belt conveyor which is placed into the drum from the
outlet, the outlet, which is located at the rear of the drum,
must be large enough for the insertion of the conveyor. Therefore
a low capacity for classification results since the volume of
muddy water which can enter the drum is small as is the amount of
classified sand which is discharged from the drum.
Here, two drums are compared in order to
understand the relationship between the capacity of the drum and
the diameter of the outlet which is located at the rear end of the
drum. Both drums have an equal length of 3.Om and an equal dia-
me~er of 2.Sm. One drum has an outlet diameter of 1.7m while
the other has an outlet diameter of l.Om. Due ot this stuctural
difference,
,.
- 2a -
1059950
the ~olume of ~uddy water which can be retained in the latter
drum is 2.3 times greater than that of the former drum since
the outlet diameter is smaller. ~his implies that if the
aforementioned be}t conveyor is no longer required, a compact
cla~si~ier which does not sacrifice the volume of sand discharged
from the classifier can be constructed.
It i9 an object of the present invention to provide
a drum-type classifier which has a cone-Qhaped discharge means
that is formed as an integral part of the classifier and is
employed for discharging the ola~sified product ~uch as sand
rather than using the conventional belt conveyor. Since the
discharge means is an integral part of the rotary drum, the
clas~ified sand is smoothly discharged from the drum as the
drum rotates.
In the case of the conventional classifier where the
rotary drum and discharging means are independently operated,
parts of the apparatus are always subject to severe frictional
wear caused by sand, giving rise to variou~ mechanical failures
or accidents, which are difficult problems and remain unsolved.
It is another ob~ect of this invention to provide a
classifier which produce~ classi~ied sand with i~proved uni~ormity
of classification set within certain limits as co~pared to the
sand that is cla~sified by the con~entional classifier~. Due to
the lowering of percentage of mud which remains in the clas~ified
sand, sand with few mud components can be obtained which can be
used to produce cement~ which have high rigidity.
It is ~till another ob~ect of this invention to provide
a classifier which is capable of separating the mud from the
larger sand componentQ and is further capable of classifying the
mud into coarse mud which is discharged through the outlet, and
fine mud which remains in the water and is discharged with it
through the water discharge outlet.
``~ lOS9950
A further object of the present invention i9 to provide
a drum-type classifier which has a settled ~and cleaning portion
which is dispo~ed between settled sand di~charge mechanis~s
whereby the apparatuB i8 capable of classifying as well as
cleaning the sand by removing the mud component which exists
in the classified sand.
~ still further object of the present invention is to
provide a drum-type classifier which can be used as an apparatus
for removing ~uspended matter from the waste liquid in such a
way that the flocculated material obtained by flocculation of
suspended matter in the wa~te liquid is discharged from the drum
during the rotation of the drum.
The construction and operation o~ this invention,
however, together with additional objects and advantages thereof,
will be best understood from the following description of the
specific embodiments when read in conjunction with the accompany-
ing drawings.
Fig. 1 is a longitudinal front view showing a drum type
sand classifier of the present invention.
Fig. 2 is a rear transverse view of the apparatus shown
in Fig. 1.
Fig. 3 is a front transverse view of the apparatus
shown in Fig. 1.
Fig. ~ is a transverse cross-~ectional view of the
apparatus of Fig. 1 taken along the line I-I.
Fig. 5 is a developed view of the drum of the apparatus
of Fig. 1 showing the relationship of the helicoid blade3, paddles
and the blockade pl~te~.
Fig. 6 i~ an expanded plan view o~ a portion of Fig. 5.
Fig. 7 iB a longitudinal ~ide view of a portion of
Fig. 6.
Fig. 8 appearing on the same sheet as Fig. 4, is a schematic
~A ~4 -
~` ' lOS99SO
view showing the direction of a falling particle in the muddy water.
Fig. 9 i9 a partial view of a feed pipc which has the
rear portion made of expanded metal.
Fig. 10 is a longitudinal cro3s-sectional view showing
a drum-type sand classifier of the second embodiment of the
present invention.
Fig. 11 is a longitudinal cross-sectional view showing
a drum-type sand ¢lassifier of the third embodiment of the
present in~ention.
Fig. 12 appearing on the same sheet as Fig. 9, is a front view
partially broken away of the classifier of the above en-bodiment.
Fig. 13 is a rear view partially broken away of the
above classifier.
Fig. 14 is a schematic view showing a plurality of
improved types of scooping paddles.
I Fig. 15 and Pig. 16 are pictorial views showing the
portion where the helicoid blades and the scoopine paddles meet
in the first or the second embodiments and also in the third
embodiment.
Fig. 17 i9 a schematic view showing the scooping paddles
oi~ the first and the second embodiments.
Fig. 18 is a longitudinal cross-sectional view of the
modified form of the classifier of the third embodiment.
; Fig. 19 is a longitudinal cross sectional view of the
classifier of the fourth and the fifth embodiments of the present
invention.
Fig. 20 is an explanatory view showlng the flow of
wàste water withln the drum of the classifier of the fourth
embodiment.
Fig. 2i i~ a cro~s-sectional view of the classifier
shown in Fig. 19 taken along line II-II.
Fig. 22 through Fig. 24 are schematical cross sectional
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`` 1059950
views of the classifier of the fourth embodiment showing the
various type~ of helicoid blades a~tached to the inner ~urface
of the drum.
In this embodiment, a rotary drum 1 encloses a feed
pipe 2 ~hich i8 concentric within the drum. The pipe 2 ha3 an
inlet 3 at the front end into which the muddy water is introduced
and an outlet 4 at the rear end. ~he rear end portion of the
pipe has a plural number of apertures 5 which may be provided,
for example, by fabricating the rear end portion of an expanded
metal mesh. The diameter of the pipe 2 gradually increases from
the front end to the rear end. Purthermore the pipe 2 is supported
by a plurality of frames 6 which extend radially from the outer
sur$ace of the rear end of the pipe 2 with one end of the
respectiYe frames 6 being secured to the rear of the pipe 2 and
the other end of the respective frame~ 6 being secured to the
upper portion of the respective helicoid blades 7. A plurality
of helicoid blades 7 of the same pitch are fixedly secured to
the entire inner surface of the drum at regular interval~ except
at the rear end of the drum 1. A plurality of paddles 8 are
radially disposed with their distal ends secured to the inner
surface of the drum 1. Each paddle 8 has a number of apertures
9. A cone-shaped chute 10 is concentric with and located at
the rear end of the drum 1; it i8 an integral part of the drum
1 with the base of the conical shape being secured to the circular
plate t 1 which in turn has an inclined surface ~ecured to the
sides of the paddles 8. A plurality of partitions 12 are fixedly
mounted on the inclined face of the conical chute t 0. An
adjustable circular plate 13 is removably mounted on the outer
periphery of a circular plate 14 which has an inclined surface
that i9 ~ecured to the sides of the paddles 8. ~ indicate3 an
outlet from which classified sand is discharged. The discharged
sand is cast into a discharge chute 15. Numeral 16 indicates a
1059950
plurality of baffle plates which are disposed along the length
of drum ~ at regular intervals. The outer portion of each
: baffle plate 16 i9 attached to a helicoid blade 7 while the
inner portion remain~ free and e~tends toward the central axis
of the drum 1. A indicates an outlet through which the super-
natant water is carried to a water discharge chute 17. The
discharged supernatant water is delivered to a reservoir by a
suitable means such as a pump (not shown in drawings). Numeral
18 indioates an adjustable circular plate which is removably
mounted on the front of plate 19, the outer periphery of which
in turn is secured to the frontmost edge of the drum 1.
With reference to Fig. 2, a plurality of teeth 20 are
fixedly attached to the outer circumference at the midsection
of the drum 1. An endless chain 21 i9 extended between the drum
1 and a first sprocket wheel 22 which i~ fixedly mounted on a
shaft 23. Numeral 25 indicates an endless chain which is
extended between the second sprocket wheel 24 and a third sprocket
wheel 26 that i5 fixedly mounted on a shaft of a motor 27.
Numeral 28 indicates a base on which the above sprockets and the
motor 27 are mounted. The drum 1 i8 rotatably supported by
plural pairs of rollers 29. Each roller 29 is fixedly mounted
on shafts 30 which have both ends journal mounted in bearings
31. Bearings 31 are fixedly mounted on a frame structure 32.
Referring to Figs. 3,5,6 and 7, a plurality of blockade plates
33 are shown which are disposed along the inner circumference
of the drum at required longitudinal positions, wherein each
plate 3~ is inserted between two helicoid blades 7 and has both
sides secured to the side edge of the blades 7 by bolts 34. The
height of the plates 33 is half that of the blades 7.
The manner in which the apparatus i~ operated i9
hereinafter described with reference to the individual operation
of the parts of the apparatu~.
`` lOS9950
The muddy water which contains sand is continuously
supplied to the front inlet 3 of the feed pipe 2 while the
drum 1 i9 rotated by the motor 27. Since the feed pipe 2 has
a diameter which gradually and continuously increa~es toward
the rear end of the pipe 2 and also has numerous apertures 5
at the rear end of the pipe, the muddy water which i~ introduced
into the pipe 2 passes through the apertures 5 and i~ dispersed
downwardly into the drum 1. Some of the remaining flow of
water may pa~s downward from the outlet 4 of the pipe. Therefore,
the muddy water loses flow energy or velocity and no vortices
occur at the point where the water leaves the feed pipe 2, which
results in improvement of the classification. The muddy water
is then forced to overflow the plurality of baffle plates 16 and
move towards the water discharge outlet A located at the front
end of the drum 1. During the above mentioned movement of the
muddy water in the direction of the water discharge outlet A,
sand particles which have a specific gravity that is greater than
that of water settle onto the bottom of the drum 1, bumping into
the baffle plates 16 and losing their flow energy. Then the
settled sand is transferred by the rotation of the helicoid
blades 7 to the rear end of the drum 1 where a plurality of
paddles 8 are disposed. Each helicoid blade 7 has many apertures
at the rear portion ~o that it can move smoothly without any flow
resistance to the water. Furthermore, the movement of sand
containing some settled mud towards the discharge outlet A i9
prevented by a number of blockade plates 33 and the blockaded
9and i8 moved along the inner surface of the drum 1 by the rota-
tion of the drum 1. When the sand i9 transferred to the "top
dead point" where it slides into the blockade plates 33, the
Yand falls onto the upper portion of the feed pipe 2 and then
is ~cattered into the water. The scattered sand or mud components
move in one of the directions in the water as shown in Fig. 8
1059950
depending on the size and specific gravity of the sand, wherein
a indicates a mud particles, b, a minute saMd particle, c, a
coarse particle and F indicates the flow direction of the muddy
supernatant water. By the repetition of the abo~e actions where
the effect is proportional to the number of blockade plates 33
that are attached, the particle ~ize distribution of the classified
sand i8 adjustable. Then, as the sand is moved along the inner
surfa¢e of the drum 1 to~ards the upper portion due to the rota-
tion of the drum 1, the water which is transported along with
the sand i9 entirely eliminated through a number of apertures
9 in each padd~le 8. When the sand which is free of water is
transferred to a location directly above the cone-shaped discharge
means 10, the sand is cast onto the inclined sur$ace of the
discharge mean~ 10.
Since a necessary number of partitions 12 are fi~edly
secured to the inclin~d surface of the discharge means 10 slides
along the inclined surface and i9 discharged $rom the discharge
outlet B~
Meanwhile, the supernatant water, which i8 the remainder
of the muddy water after the sand of the required size range
has æettled onto the bottom of the drum 1, is caused to overflow
from the discharge outlet A into the water discharge chute 17.
The water is then transferred to a reservoir by a suitable means
such as a power-operated pump.
~ he second embodiment discloses a drum-type classifier
which is characterized by having water separation paddles
disposed coaxially one subsequent to the other at the sand dis-
charge end of the drum. Although when producing sand, separation
into uniform particle sizes i9 ne¢essary; decrea~ing the amount
of mud remaining in the classified sand is also important in
raising the quality of the sand since the above quantity of mud
will in$1uence the strength of the concrete produced using the
sand.
-- 9 ~
10599S0
For the purpose of improving the abo~e quality,
conventional claæsifiers have made various kinds ~f improvements
in the water separation paddle3. However, ~ince the sand is
scooped fro~ muddy water, the removal of the mud in the classified
sand cannot be thoroughly achieved. It i9 especially difficult
to decrease the quantity of mud in the final product when minute
sand particles must be classified from very muddy water.
This embodiment has resolved the above problems by
disposine the water separation paddle~ coaxially with one
subsequent to the other. In short, the mud component contained
in the cla~sified sand is drastically decreased by the combina-
tion of the first ring of water separation paddles which ~coop
the minute sand particles from water containing a relatively
large quantity of mud and the second ring of separation paddles
which are disposed subsequent to the above first separation
paddle~ and which clean the classified sand with the water.
In this embodiment as shown in ~ig. 10, at the rear
portion of a settled sand discharge mechanism C in the axial
direction of the drum 1, another settled sand discharge mechanism
C~ which has a similar construction to mechanism C is disposed
coaxially with mechanism C, wherein numeral 14' indicates a
ring-like weir plate. 8' indicates water ~eparation paddle~,
numeral 10' indicates a cone-shaped chute, numeral 12' indicates
partition plates, numeral 11' indicates a ring-like side plate
and numeral 7' indicates helicoid spirals.
A clean water 8upply tube 35 i8 disposed within the
settled sand discharge opening B' from the outside of the drum
1 such that clean water is supplied to the settled-sand cleaning
portion F which i8 enclosed between the ring-like weir plates 14
and 14' and the inner peripheral wall of the rear portion of the
drum 1 where the settled sand i~ cleaned.
lhe settled sand such as minute sand which is dischar~ed
- 10 -
1059950
by the ~ettled ~and discharge mechani~m C still contains a
sizeable quantity of mud since the water separation paddles 8
rotate in water which conta1n~ a great quantity of mud.
Due to the above mentioned construction, if this settled
sand is charged into a settled sand cleaning portion F, which is
enclosed by the ring-like weir plates 14 and 14' and the rear
portion of the drum 1, the mud components which adhere to the
minute sand particle~ are wa~hed away by the clean water which
i~ charged through the clean water supply tube 35 and the clean
settled sand is discharged from the outlet of the drum 1 by the
settled product discharge mechanism C' which i8 similar in
construction to mechanism C. Furthermore since the settled
sand discharee openings B and B' of the ring-like weir plates
13 and 13^ have a smaller diameter than that of the supernatant
water discharge opening A, muddy water with a smaller amount of
mud is discharged into the 3ettled sand cleaning portion F 90
that the density of the mud component of the water is maintained
at a very low level whereby the quantity of mud contained in the
classified minute sand, is lowered to the extremely low percentage
of less than one per cent. Meanwhile the supernatant water which
contains the mud component is discharged from the drum 1 through
the æupernatant water discharge opening A of the ring-like weir
plate 19.
In this embodiment, the inventor describe3 a classifier
which i9 capable of cla~sifying as well as cleaning the ~and by
removing the mud component which e%ists in the classified sand.
However, it should be noted that the apparatus of this embodiment
is also applicable for use in classifying components which are
settlable and are contained in other kinds of liquids.
As has been described heretofore, since the cleaning
of classified sand is conducted simultaneously with the cla3sify-
ing operation, it is unnecessary to spend extra ti~e cleaning
1059950
the classified sand and the quality of the settled product i9
improved.
Thi~ embodiment discloses a rotary-type classifier
whose primary purpose is to improve the quality of the clas~ified
~ettled sand and is characterized by having an improved type of
water separation paddles. ~he inventor has disclosed rotary-type
classifiers with great practical merit heretofore. However,
referring to the above classifiers as shown in ~ig. 16 and Fig.
17, at the ~ettled sand discharge end of the drum body a', a
plurality of water-separation or scooping paddles b', each of
which has a multiplicity of apertures formed therein is radially
secured to the inner periphery of the drum 1 in an axial direc-
tion. ~here~ore, the portion or point where the discharge end
of the helicoid blade d~ and the scooping plate b' meet, forms
a considerably acute angle. This implies that the settled sand
e' which is transferred to the settled sand discharge end by a
plurality of helicoid blades te~ds to accumulate at the deflected
or bent portions while a "dam" is formed between the accumulated
settled sand e' and the ring-like weir plate f' is for discharging
the settled product. A multiplicity of aperture~ that are formed
in each scooping plate, can not separate the water sati~factorily
due to the restriction on the size and number of apertures, there-
fore the discharged sand ~till contains a considerable amount of
water.
Generally ~peaking, the cleaning operation is conducted
after the classification of the settled sand when the settled
sand contain~a great amount of impurities.
This embodiment provides a rotary-type classifier which
can produce a classified product of improved quality by efficient-
ly separating out the water without necessitating the abovecleaning operation. The classifying and cleaning operation3 are
simultaneously conducted as desired, corresponding to the ~uantity
1059950
of impurities relative to the liquid to be treated.
~he apparatus of this embodiment is hereinafter
described in great detail in conjunction with the attached
drawings except for the means which are described in the previous
embodiments.
In this embodiment, D indicates a dam formed by the
cylindrical drum 1 and the two end weir plates. lhe ring-like
weir plate 19 located at the front end of the drum 1 has a
circular opening A greater than the opening B of the rear ring-
like weir plate 14 so tha-t the supernatant water will overflow
through the opening A.
With respect to the ~cooping paddles 8 which form the
essential part of this embodiment, the peripheral portion 8a
of the above scooping paddle 8 has a height equal to the height
of the adjoining helicoid blade 7 and i3 also deflected at a
desired angle from the axial direction of the drum.
Due to the above construction of the helicoid blades as
shown in Figure 15, the angle formed by a helicoid blade 7 and
the peripheral portion 8a of the scooping paddle 8 is approximately
180 90 that the settled product E which i9 transferred from the
helicoid blade 7 does not accumulate at the deflected area but
accumulates at the deepe~t corner area formed by the scooping
paddle, drum 1 and the weir plate 4. In other words, the 90
called "dam" which appears between the ring-like weir plate 14
and the accumulated settled product in conventional apparatuses
is not formed 90 that the water separation is effectively
conducted a~ the accumulated settled product i~ lifted up by
the peripheral portion 8a of the individual scooping paddle 8
which utilizes the above-mentioned water separation apertures 13.
Furthermore it is desirable that the peripheral portion
8a of the scooping paddle be nearly sevcred from the inner
portion 8b thereof as shown in Fig 14 and that the triangular
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105~950
opening 8c i9 formed by disposing the inner portion 8b slightly
behin~ the peripheral portion 8a relative to the rotation of
the drum 1. The above mentioned con~truction of the soooping
paddle relative to the helicoid blade can be formed by twisting
the scooping plate.
The triangular cut 8c acts as an opening through
which the water pas~es 80 that the energy required to rotate
the drum is decrea~ed as the settled product is elevated.
Fig. 18 describes the clas~ifying apparatus with two
settled product di~charge mechanisms which are sequentially
disposed in parallel and perpendicular to the axial direction
at the rear of the drum. Each mechani6m comprises a plurality
of scooping paddles with apertures therein.
In the above construction, the central openings B, B'
of the ring-like weir plates 14, 14' have diameters Y, Y' which
are smaller than the diameter X of the opening A of the ring-
like weir plate 19. The above diameter Y' i3 smaller than the
diameter Y although the diameter Y' can be the same as the
diameter Y in some case.
Furthermore, as mentioned above, the helicoid blades
7' can be employed between the discharge mechanisms C and C'
~o that the settled product di~charged by the settled sand
discharge mechanism C is transferred to the next settled-product
discharge mechanism C'.
In addition, the clea~ water supply tube 35 is disposed
through the opening B' of the final ring-like weir plate.
Accordingly, the ¢lean water discharged from the
supply tube 35 is charged between the above-mentioned settled
product discharge mechani~ms C, C', thus forming a cleaning
chamber F.
Due to the above-mentioned settled product discharge
mechanisms C and C', the settled product discharged by the
- 14 -
~A
~os99so
helicoid blades 7 i8 subject to a circular rotation operation
which consists of scooping up the sand, separating the water
from the sand and discharging the sand by gravity coupled with
the water separation effects of scooping paddles 8 and 8' so
that the product finally discharged from the drum is almo~t
entirely free from impurities such as mud and shows a greatly
improved quality.
As has been described heretofore, the apparatus of
this embodiment can achieve total water separation when the
settled product is scooped up by the scooping plates.
This embodiment discloses a drum-type classifier
which i9 characterized by a water-flow regulating structure
which prevents the agitation of the settled product between
the helicoid blades that is caused by water energy at the point
where water fall~ into the drum.
The rotary-type drum classifier employ 8 a classifying
method whereby the settled product is separated from the raw
or waste liquid by specific gravity of the product so that the
dam of waste water which is formed within the drum remains as
calm as possible.
However it is hardly possible to obtain calmness at
the point where the water continuously falls into the drum, so
that heretofore, in order to weaken or disperse the flow energy
at the above point, several methods including one which adopt~
a screen at the outlet portion of the feed pipe, have been
diæclosed.
~ owe~er, the above methods are less efficient once the
product which is settled between each two helicoid blades is
agitated by the water energy caused by the rotation of the drum
in order to transfer the settled product to the rear of the
drum. The above phenomenon occurs especially when classifying
mud composed of extremely minute particles, which range downward
~ os99so
in size 200 ~. The above classifying cannot be conducted
sati~factorily by conventional methods.
The manner in which is operated the apparatus of this
embodiment which has resolved the above problem is herein-
after explained in conjunction with the drawing of ~ig. 19 and
20 wherein the apparatus is characterized by having a circular
cov~ring plate 36 which i8 disposed within the dru~ 1 such that
the co~ering plate 36 covers the rear of the helicoid blades 7.
~ hen waste water is continuously fed into the 310wly
rotating drum 1 by way of the waste water introduction pipe
2a, the waste water falls into the drum 1 from the outlet of
the feed pipe 2 and forms a dam which has the cross-section of
a segment of a circle.
The waste water whi¢h is charged into the drum ~ first
- hits the side separation plate 11 which is disposed at the rear
of the feed pipe 2 and flows in the drum loses its flow energy
by hitting ring-like baffle plates 16.
Since vortices are formed at the point just below the
outlet of the feed pipe 2 due to the falling of the waste water,
this embodiment has the circular covering plate 36 secured to
the outer periphery of the side plate 11 ~uch that the covering
plate 36 cover~ the rear portions of the helicoid blades 7 for
the purpose of changing the flow direction of the wa~te water
to a horizontal direction at this point.
Since classifiers described heretofore do not ha~e the
circular co~ering plate 36, the waste water which falls into
the drum from the outlet of the feed pipe 2 flows into the place~
between the helicoid blades 7 at a location below the outlet
of the feed pipe 2 a~ shown in the dotted line and thereby
causes the ~ortices.
Accordingly, the smaller the particle size of the
product which settle~ between each two helicoid blade becomes,
A 16 _
~ 59 9 50
the greater the ~ettled product is agitated. ~herefore, the
settled product i~ not tran~ferred toward the scooping paddles
8 which results in the ~upernatant water containing the abo~e
whirled once-settled product.
In thiæ embodiment, as has been described above, by
employing the circular covering plate 36 which covers the
helicoid blades 7 at the above-mentioned location, the flow
direotion can be changed so that the occurence of vortice~
between the helicoid blades 7 can be pre~ented or regulated.
It is to be noted, however, that there mu~t be enough
space between the circular covering plate 36 and the ring-like
baffle plates 16 where the wa~te water i5 first 80 that the
settled product doe~ not accumulate on the inner wall of the
circular covering plate 36.
In this manner the minute particle~ contained in the
waste water generally settle onto the~bottom of the drum 1
between the helicoid blades 7 at a location far from the outlet
of the feed pipe 2, namely, the point close~t to the supernatant
water discharge A where the dam, formed by the waste water is
the most stable. After settling, the particles are transferred
along the helicoid blade~ 7 toward the rear of the drum 1 by
the rotation of the drum 1 as shown in ~ig. 19 and reach a loca-
tion just below the outlet of the feed pipe 2.
Since the water energy of the falling waste water does
not affect the water between the heIicoid blades which are
covered by the co~ering plate 36, the settled minute particles
are not affected by the energy and pass below the circular
covering plate 36 and are smoothly charged into the scooping
paddle3 8 which are radial~y disposed subsequent to the helicoid
blades 7. ~he thusly transferred particles are then raised
upward by the ~cooping paddle~ while being ~eparated from the
water by the rotation of the drum and are di~charged downward
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onto the cone-shaped chute 10 which is disposed in the center
of the plurality of scooping paddles 8 and the particles out
of the drum 1
~ ig. 19 shows the apparatus of this embodiment most
precisely wherein the rear of the feed pipe 2 is integrally
attached to the back of the cone-shaped chute 10 and a desired
number of side openings 37 are formed in the rear of the feed
pipe 2.
~ urthermore the apparatus as shown in Fig. 19 has a
drum which is proportionally shorter in length relative to the
diameter when compared to conventional apparatuses, but the
volume of water contained in the drum 1 is kept the same. There-
fore, the dam formed in the drum can have a greater depth thaa
that of conventional apparatu~es. ~he greater depth of the dam
coupled with the effect caused by the circular covering plate,
prevents the a~itation of the settled product as much as possible
so that the classifying efficiency of the apparatus is greatly
improved.
This embodiment discloses a rotary-type classifier
which is most suitable for separating and discharging flocculated
material obtained by flocculating suspended matter in waste
water,
~ he inventor has already disclosed a rotary-type
classifier for classifying sand and the like in the foregoing
embodiments. However, when the classifier is directly applied
to the disposal of waste water which may contain suspended
matter it does not work well due to its construction. It is
because the flocculated material which i9 produced as coloidal
particles by adding a high molecular weight coagulant to the
waste water have a lower specific gravity compared to sand so
that even when they are settled between the helicoid blades
which are fi~edly secured to the inner peripheral surface of
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the dru~, the settled flocculated product is dispersed into the
waste water again by the rotation of the drum and can not be
smoothly transferred to the discharge end of the drum.
In this embodiment as shown in Fig. 19 through Fig. 24,
numeral 38 indicates a space confined by the helicoid blades
which are formed to serve the complete transferring of the
settled flocculated material from the drum and G indicates
flocculated material or particles.
In Fig. 22 through 24, helicoid blades with vari OU9
types of cross-sections are shown.
The manner in which tha apparatus of this embodiment
i8 operated is hereinafter disclosed.
First, the waste water i9 charged into the drum 1
through the waste water introduction pipe 2a and the inversely
tapered feed pipe 2. Thehigh-molecular weight coagulants can
be added either before or after the waste water is charged into
the drum 1 to form the flocculated material. The waste water
which is then charged into the drum 1 forms the dam within the
drum which has the cross-section of a segment of a circle. The
waste water in the drum is transferred toward the supernatant
water discharge opening A. In the above flow of the water,
the flocculated material suspended in the waste water is caused
to settle downward by the action of the ring-like baffle plates
16 and settles into the areas between each two helicoid blades
7. The helicoid blades 7 which are an integral part of the
drum rotate in the direction of the arrow as shown in Fig. 21.
Since the space 38 between each two helicoid blades
7 has a narrowed opening directed in the rotating direction of
the drum 1, the flocculated particles G which settle between
each two helicoid blades 7 do not escape from the narrowed
opening due to the configuration of the helicoid blades 7 even
though they may be displaced from (p) to (q) within the space
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a~ the drum i8 rotated.
In this manner the flocculated material which is
confined to the ~pace i9 smoothly transferred along the ~urfaces
of the helicoid blades 7 toward the rear of the drum 1 and
subsequ~ntly is charged onto the scooping paddles 8 which are
radially disposed at the rear of the drum 1. The flocculated
material is then raised upward by the scooping paddle~ correspond-
ing to the rotation of the drum 1 80 that the water i8 ~eparated
from the scooped flocculated material and the material slides
forward onto the paddle~, then onto the cone-shaped chute 10
which eventually di~chargea the flocculated material through
the settled product discharge opening B. The supernatant water
which is free from the above flocculated material i9 di~charged
from the supernatant water discharge opening A.
As has been described heretofore according to this
invention, since the heli¢oid blades 7 are shaped and secured
to the inner peripheral surface of the drum in such a way that
the space 38 between each two helicoid blades 7 has a narrowed
upper opening in a direction which corresponds to the rotating
direction of the drum 1, even the settled product of a low
specific gravity such a~ a flocculated product can be smoothly
tra~sferred whereby the removal of flocculated material can be
achieved.
According to this invention, the apparatus is
characterized by the following itemized advantages:
1) The sand which i8 contained in the muddy water is
to some extent forcibly caused to settle onto the bottom of
the drum 1 by employing a number of heliooid blades 7; therefore,
the volume of minute sand particles which overflow with the
supernatant water can be limited to as small an amount as possible,
resulting in remarkable classification efficiency.
2) Since the feed pipe 2 is constructed as an integral
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part of the rotary drum 1 and, therefore, rotates with the drum
1, the sand is uniformly distributed over the entire inner
sur~ace of the drum 1 so that wear also occur~ evenly on the
entire surface of the drum 1 rather than on certain portions
only, which enables the apparatus to withstand long use.
3) Since the feed pipe 2 has a dia~eter which gradually
increases toward the rear end and has a number of apertures 5
at the rear end, the muddy water charged into the pipe 2 passes
through the apertures 5 and i8 dispersed into the drum 1. There-
fore, the muddy water loses its flow energy or speed and thereis no occurrence of vorteces at the place where the muddy water
drops into the drum 1.
4) Each helicoid blade 7 has a number of apertures
at the rear portion, so that the blade can be rotated using
less power since the blade incurs less resistance to the flow
of the muddy water.
5) The attachment of a plurality of ba~fle plates 16
to the helicoid blades 7 enables the positive agitation of the
muddy water by which the sand is forcibly classified and alsP
assures improvement of the settling efficiency of the sand by
lessening the flow speed of the muddy water.
6) In the muddy water which is introduced into the
drum 1, the coarse sand easily settles to the bottom of the
drum 1 as soon as the muddy water drops into the drum 1 from
the feed pipe 2 and is transferred to the discharge outlet B.
The minute or fine sand, which, unlike the coarse sand, does
not settle instantly qtrikes the paddle plates 15 as it moves
in the muddy water towards the water discharge outlet A, whereby
the fine sand is also urged to settle on the bottom of the
drum 1.
7) The smooth and natural movement of the settled sand
is assured since the sand which has settled onto the bottom of
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the drum 1 is transferred in the direction of the discharge
outlet B simply by the rotation of the drum.
8) ~he product (the cla~sified sand) is automatically
discharged from the drum 1 by the simple rotation of the drum 1.
9) Since there are no driving means such as shafts or
bearing nor any mean~ for conveying sand within the rotary
drum 1, all of which are ll-affected by water, mechanical
failures are completely eliminated.
10) Since in the apparatus of this invention it is
unnecessary to employ a belt conveyor at the discharging outlet
A, the diameters of these two outlets A and B are both made as
small as possible, whereby the amount of settled sand in the
drum 1 of this invention can be more than twice that in the
conventional apparatus, which results in an improvement in the
classifying performance of the apparatus.
11) The location and number of rows of blockade plates
33 can be varied to correspond to the amount of raw material
to be introduced, i.e., the capability of the apparatus to
classify sand in a much wider range of size~ is made possible.
12) Since the mud component that adheres to the sand
particles is removed by the agitation which is caused by a
plurality of blockade plates 3~, the degree of uniformity, set
within certain limits, of the classified sand is remarkably
increased.
13) ~he particle size distribution of the product, the
classified sand, is adju~table by way of increasing or decreasing
the number of blockade plates 33.
14) If desired, a plurality of discharging means will
be employed at the rear of the drum 90 that the cleaning of
classified ~and is conducted simultaneously with the classifying
operation.
15) If desired, the helicoid blades are secured to the
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inner wall of the drum such that the space between each two
helicoid blades has the narrowed opening directed toward the
rotating direction of the drum whereby the settled product of
a low specific gravity such as a fl~.cculated material can be
removed.
