JP2000210591A - Centrifugal dewatering machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the dewatering capacity of a horizontal centrifugal dewatering machine, to save energy, and to reduce cost. SOLUTION: In a centrifugal dewatering machine in which a screw conveyer is housed in a bowl 1 rotating at a high speed, the bowl 1 is formed so that the ring-shaped front end wall 4 protruding slightly with the axis turned to the front end of a horizontal straight barrel part 2 is projected, and a filtrate discharge part 6 composing a discharge hole and a screen is formed on the rear surrounding wall of the barrel part 2. In the screw conveyer 10, raw liquid can be supplied to the rear part opposite to the discharge part 6, and in a mud discharge opening part, a back pressure adjusting body 20 which adjusts the opening of the opening part and controls the discharge of dewatered cake is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal dewatering apparatus for concentrating and dewatering sewage sludge and industrial wastewater, collecting solids and separated water by centrifugal force.

[0002]

2. Description of the Related Art Conventionally, a decanter type centrifugal dehydrator has been generally used for solid-liquid separation of sludge and the like. As shown in FIG. 11, this dehydrator is formed by connecting a conical cylinder 31 to the tip of a horizontally long straight body portion 30 and is a high-speed rotating bowl (outer rotating cylinder).
A screw conveyor 10 provided with a spiral wing 12 in an inner cylinder (inner rotating cylinder) 11 and rotated with a relative speed difference from the bowl 1 is accommodated in the inner cylinder 1. Is supplied, and solid-liquid separation is performed by centrifugal force. The dewatered cake b settled and separated by the centrifugal force in the bowl 1 is sequentially raked toward the front end by the spiral blade 12, and further subjected to a consolidation and dewatering action in the conical cylinder 31 to discharge the front end. It is discharged out of the machine from the mud hole 5,
The separated liquid C overflows from a discharge hole 32 provided in the rear end wall of the bowl 1 on the opposite side and flows out.

In this decanter type centrifuge, the bowl 1
In order to store the filtrate in the inside, in order to prevent the filtrate from being discharged from the discharge port 5 for discharging the cake, the front end is increased to a level (water level) equal to or higher than the discharge hole 32 for the separated liquid. The feature is that a conical cylinder 31 with a small diameter is required.

[0004]

However, in the above conventional decanter-type centrifugal dehydrator, when the undiluted solution a is supplied to the center of the bowl 1, a high force is applied to the bowl body 30 immediately after the supply. Although the solid-liquid separation is performed by the place (approximately 2000 to 3000 G), the distance (diameter) from the center of rotation of the bowl conical portion 31 from which the dewatered cake b is discharged becomes short. Only the cake having a relatively high moisture content close to the rotation center is discharged, and the cake having a relatively low moisture content far from the center of rotation stays and is not discharged.

Further, since the dewatered cake b passes through a large inclined conical cylinder for discharging the water beyond the water level in the bowl, slipping occurs at this portion, and the discharge becomes poor, and the separated liquid c is removed from the dewatered cake. There is a drawback such as retention in b, resulting in poor dewatering. Since the dewatered cake to be discharged has a relatively high water content close to the rotation center of the straight body portion 30, the rotation of the bowl 1 is reduced in order to lower the water content of the discharged dewatered cake. Increase the number more than necessary (about 20
00-3000rpm). Therefore, large power is required.

The present invention has been made to solve the problems in the decanter-type centrifugal dehydrator as described above.
Dehydration efficiency can be improved by promoting dehydration,
An object of the present invention is to provide a straight-body centrifugal dehydrator capable of reducing the number of rotations of a bowl, saving power and simplifying and miniaturizing the apparatus.

[0007]

According to the dehydrating apparatus of the present invention,
In order to enable efficient solid-liquid separation and prompt drainage of the separated liquid, a filtrate discharge part is provided on the peripheral wall at the rear of the bowl or the outer peripheral part of the bowl rear end wall. This is done in the back of the bowl near the discharge. As a result, the feed stock solution is promptly separated and drained, so that the occurrence of a water surface in the bowl can be suppressed, and the transport distance and residence time of the dewatered cake can be increased. And the bowl was formed in a straight body type, the front end of which was used as a sludge outlet having a slightly smaller diameter, and a back pressure adjusting body for adjusting the width of the sludge outlet was provided facing the sludge outlet. It is assumed.

Further, the dewatering device of the present invention may be provided with a means for scraping off sludge adhering to the screen of the filtrate discharge part. As a result, the function of the filtrate discharge section is maintained satisfactorily, which is suitable for the treatment of a stock solution having a high concentration, and enables continuous operation for a long time.

[0009] In the dewatering device of the present invention, the bowl can be provided with an inclined body extending slowly and long following the straight body, and the bowl is relatively shaped. Following the short first straight body, a short inclined body and a second straight body slightly smaller in diameter than the first straight body can be provided in series.

In the dewatering apparatus of the present invention, the filtrate discharge portion may be provided on both the peripheral wall and the rear end wall at the rear portion of the bowl, and the scraping blade for adhering sludge may be provided in connection therewith. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the apparatus of the present invention, FIGS. 3 and 4 show other embodiments in which the shape of the bowl is changed, respectively, and FIG. 5 shows the position of the filtrate discharge section. 6 to 9 show another embodiment in which a sludge scraping blade is provided, and FIG. 10 shows another embodiment of the back pressure adjusting body.

In FIG. 1 and FIG. 2, reference numeral 1 denotes a high-speed rotating bowl (outer rotating cylinder) in which a screw conveyor 10 having a rotating drum (inner rotating cylinder) 11 provided with a spiral blade 12 is provided.
The bowl 1 is accommodated so as to be rotated with a relative speed difference. A supply chamber 13 having a supply port 14 for the undiluted solution a is provided at the rear of the rotary drum 11, and a supply pipe 15 passing through the axis of the rotary drum is connected to the supply chamber 13. In the illustrated example, the supply pipe 15 is passed from the rear side of the rotating drum 10,
Conversely, it may be passed from the front side of the rotating shaft.

The bowl 1 is provided with a rear end wall 3 on a straight body portion 2 having the same diameter over the entire length, and a short annular front end wall 4 tapered and inclined at a front end. Between the rotating body 11 and the rotating body 11, there is formed a mud hole 5 slightly narrower than between the inner circumference of the straight body part 2 and the rotating body 11.

A filtrate discharge portion 6 is provided on the peripheral wall at the rear portion of the straight body portion 2 which is the rear portion of the bowl 1. As shown in FIG. 2, for example, the filtrate discharge portion 6 includes a plurality of discharge holes 7 formed along the circumferential direction of the straight body portion, and a porous plastic molded body, a wire mesh, And a screen 8 made of a sintered metal, filter cloth or the like. In addition, the structure of the filtrate discharge part 6 is not limited to the above-described structure, and the structure can be appropriately changed as long as it is a combination of the discharge hole 7 and the screen 8.

Further, facing the mud outlet 5 of the bowl 1,
A back pressure adjusting body 20 for adjusting the opening degree, ie, the size, of the mud outlet 5 is provided. The back pressure adjusting body 20 has a cylindrical shape,
The outer periphery of the tip facing the drain port 5 has a tapered conical surface 21.
When it is fitted to the outside of the rotary drum 11 of the screw conveyor 10, it can be adjusted forward and backward in the axial direction (arrow Ero). Therefore, the back pressure adjusting body 20
Is moved forward in the direction of the arrow a which is the rear end direction of the bowl 1, the mud hole 5 is caught, and conversely, if it is retracted in the direction of the arrow B, the mud hole 5 is spread. become.
As shown in FIG. 10, the back pressure adjusting body 20 may have a cylindrical shape in which the surface facing the drain port 5 is perpendicular to the axis of the screw conveyor 10.

The undiluted solution a to be dehydrated enters the supply chamber 13 through the supply pipe 15 as shown by the arrow, and enters the bowl 1 through the supply port 14.
That is, it is supplied into the annular space between the rotating drum 11 and the straight drum portion 2. Then, due to the centrifugal force of the bowl 1, which rotates at a high speed, it adheres to the inner peripheral surface of the straight body portion 2 to perform solid-liquid separation by centrifugal force, and the separated liquid c, which is the separated liquid, is filtrated. The water is filtered by the screen of the discharge part 6 and discharged out of the machine through the discharge hole 7.

The dewatered cake b containing the solid content and the slightly remaining liquid content is raked toward the front end of the bowl 1 by the spiral blades 12 of the screw conveyor 10 and further subjected to a separating action by centrifugal force. The separation of the remaining liquid proceeds, and the separated liquid c is discharged from the discharge hole 7. And
The dewatered cake b and the like conveyed to the front portion of the bowl 1 are subjected to a compaction action between the annular front end wall 4 at the front end and the conical surface 21 of the back pressure adjusting body 20, and the trapped drain port 5 is sandwiched between them. It will be discharged more out of the aircraft. At this time, a desired dewatered cake can be obtained by adjusting the advance and retreat of the back pressure adjusting body 20 according to the properties of the stock solution a and the like. In addition, a stable dewatered cake can be obtained by automatically controlling the forward / backward adjustment of the back pressure adjusting body by detecting the consolidation state (transport torque) of the dewatered cake.

In the apparatus of the present invention, as described above, the undiluted solution a
Is supplied to the rear part of the bowl 1, and the separated liquid c is forcibly discharged immediately by the centrifugal force from the filtration discharge part 6 provided at the rear part of the bowl 1. Therefore, there is almost no water level in the bowl 1 as in the prior art. Since most of the solid-liquid separation and the discharge of the separated water c are performed at the rear portion of the bowl 1, no turbulent flow occurs in the bowl 1, and the residence time of the dewatered cake b becomes longer. Therefore, there is no need for a long conical cylinder part at the end of the straight body as in the past,
The overall length of the bowl is also short.

In the present invention, the bowl 1 can be embodied in a different form. 3 and 4 show the respective embodiments. In the embodiment of FIG.
In the form of a relatively short length of the straight body part 25, a relatively long gentle slope body part 26 whose tip diameter is slightly smaller than the diameter of the straight body part 25 is formed in front of the relatively short straight body part 25, This inclined body 26
As a result, the dewatered cake b conveyed tends to accumulate near the discharge port 5. The filtration / discharge unit 6 is provided on a straight body 25 at the rear of the entire length of the bowl 1. Other configurations are the same as those in the embodiment of FIGS.

In the embodiment shown in FIG. 4, the shape of the bowl is changed to a relatively short first straight body 27, followed by a short inclined body 28.
However, further ahead, a second straight body portion 29 having a diameter slightly smaller than the diameter of the straight body portion 27 is provided to be extended, and the second straight body portion is provided.
At the tip of 29, an annular front end wall 4 that projects short in the axial direction
Are formed. Also in this case, the filtrate discharge part 6 is provided in the first straight body part 27. Other configurations are shown in FIGS. 1 and 2.
This is the same as in the embodiment. In the embodiment of FIG. 5, the filtrate discharge part 6 is changed to the outer peripheral part of the rear end wall 3 instead of the peripheral walls of the straight body parts 2, 25, 27 as described above. Other configurations are the same as those in the embodiment of FIGS.

FIGS. 6 and 7 show an embodiment in which a means for scraping off the sludge adhering to the filtrate discharge portion 6 provided on the peripheral wall of the straight body portion is provided. In this embodiment, the screw conveyor 10 has a spiral wing corresponding to the filtrate discharge section 6.
A part of 12 is cut away, and a plurality of sludge scraping blades 16 attached radially to the screen 8 with the tip sliding on the screen 8 are radially mounted on the rotary cylinder 11 at that part. This scraping wing
It is preferred that the slug 16 not only scrape off the sludge adhering to the screen 8 but also maintain an angle with respect to the axis so as to have a conveying force for the sludge and the dewatered cake.

Further, in the apparatus of the present invention, a discharge part for filtrate can be further provided on the rear end wall 3 of the bowl 1. That is, in the apparatus of this embodiment, FIG.
As shown in FIG. 9, the filtrate discharge part 6 provided on the peripheral wall of the straight body part
In addition, a filtrate discharge part 18 is provided on the outer peripheral part of the rear end wall 3. The filtrate discharge portion 18 may be formed by the discharge hole 7 and the screen 8 as in the previous embodiment, or may be discharged along the circumferential direction of the outer peripheral portion of the rear end wall 3 as shown in the drawing. A long hole 7 is formed, and a screen (not shown) is attached inside the hole 7. In the case of this embodiment, in addition to the above-mentioned scraping wings 16, the sludge scraping wings 19 of the sludge adhered to the screen 8 in sliding contact with the screen 8 of the filtrate discharge part 18 are rotated by the rotating cylinder of the screw conveyor 10. Mounted on the rear end of 11 In addition, the scraping blade 19 also removes the scraped sludge from the bowl 1.
Is preferably formed so as to be able to be sent out in the direction of the tip. By doing so, the separated water c at the rear end of the bowl 1 that is easily stagnateed can be discharged well.

The embodiments shown in FIGS. 5 to 9 can be applied to the embodiments shown in FIGS.

[0024]

As described above, according to the centrifugal dewatering apparatus of the present invention, the discharge portion of the filtrate (separated liquid) is provided on the peripheral wall farther than the axis of the rear portion of the bowl, the outer peripheral portion of the rear end wall, or both. As well as supplying the undiluted solution into the rear part of the bowl with the filtrate discharge section, and providing a back pressure adjusting body at the discharge port, the opening of the discharge port can be adjusted. It has many excellent effects as follows.

(1) Since the supply of the undiluted solution and the discharge of the filtrate are close to each other, immediately after the undiluted solution is supplied, centrifugal separation and discharge of the separated liquid are performed. Even if the number is reduced, the same dewatering efficiency as that of the conventional machine can be obtained, and less power is required.

(2) Since the undiluted solution is centrifuged immediately after the supply and the filtrate is discharged, the water surface is hardly formed in the bowl. Therefore, the water surface is formed in the bowl as in the conventional machine. There is no need to provide a large conical cylinder with a large aperture, and it is sufficient to provide a front end wall that is slightly on a business trip, and the length of the bowl can be shortened because the transport distance of the dehydrated cake can be short, In addition, since there is no need to provide a long conical cylinder, the cost of the apparatus can be greatly reduced.

(3) Since the supply position of the undiluted solution and the discharge position of the filtrate are close to each other and there is almost no water surface in the bowl, there is almost no backflow in the bowl, and the cake can be transported more smoothly due to the dewatering rate.

(4) By moving the back pressure adjusting member provided at the mud outlet portion forward and backward, the degree of opening of the mud outlet portion can be adjusted, and the compaction action can be freely adjusted by suppressing the discharge of the dewatered cake. The dehydration rate can be improved, a stable dewatered cake can be obtained, and it can be widely applied to various types of sludge such as sludge having a property that is difficult to dewater.

(5) In a device provided with means for scraping off sludge adhering to the screen in the filtrate discharge section, clogging of the screen can be prevented, and discharge of the separated liquid can be carried out smoothly at all times. It can be performed without any trouble, and the processing efficiency can be maintained high.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing one embodiment of the device of the present invention.

FIG. 2 is an enlarged side sectional view of a filtrate discharge part.

FIG. 3 is a side sectional view showing another embodiment of a bowl configuration.

FIG. 4 is a side sectional view showing still another embodiment.

FIG. 5 is a side sectional view showing an embodiment in which a filtrate discharge section is provided on a rear end wall.

FIG. 6 is a side sectional view showing an embodiment provided with a sludge scraping blade.

FIG. 7 is an enlarged front view of the same half.

FIG. 8 is a side sectional view showing an embodiment in which a filtrate discharge section is provided on the peripheral wall and the rear end wall of the straight body section and sludge scraping blades are provided.

FIG. 9 is an enlarged front view of the same half.

FIG. 10 is a side sectional view showing another embodiment of the back pressure adjusting body.

FIG. 11 is a side sectional view showing a conventional decanter-type device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bowl 2 Straight body part 3 Rear end wall 4 Front end annular wall 5 Drainage port 6, 18 Filtrate discharge part 7 Drainage port 8 Screen 10 Screw conveyor 11 Rotary drum 12 Spiral wing 14 Supply port 16, 19 Pressure adjusting body 21 Conical surface 25 Straight body 26, 28 Inclined body 27 First straight body 29 Second straight body

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[Procedure amendment]

[Submission date] June 1, 1999 (1999.6.1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 5

FIG. 3

FIG. 4

FIG. 6

FIG. 7

FIG. 8

FIG. 9

FIG. 10

FIG. 11

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Noboru Suzuki 3-1-3 Nihonbashi Muromachi, Chuo-ku, Tokyo Kubota Tokyo Head Office (72) Inventor Yasuyuki Yoshida 1-2-47 Shikitsuhigashi, Naniwa-ku, Osaka-shi Kubota Osaka Co., Ltd. (72) Inventor Hiroyuki Matsui 1-2-47 Shikitsuhigashi, Namiwa-ku, Osaka-shi Kubota Osaka Co., Ltd. (72) Inventor Takashi Uchikawa 2-1-6 Nishijima, Nishiyodogawa-ku, Osaka Co., Ltd. Inside the Kubota Shin-Yodogawa Environmental Plant Center (72) Inventor Tetsuo Ohinata 1-8-1, Shinjuku, Shinjuku-ku, Tokyo F-term in Kotobuki Giken Kogyo Co., Ltd. 4D057 AA10 AA11 AB01 AC01 AC06 AD01 AE03 AF05 BC11 BC15 4D059 AA03 BE38 CB06 CB07 CB09 CB18 CB27

Claims (5)

[Claims] 1. A centrifugal dewatering apparatus in which a screw conveyor rotated at a relative speed difference is accommodated in a bowl rotated at a high speed, wherein the bowl is attached to a tip of a horizontal cylindrical straight body by an axial center. Filtrate discharge formed by providing an annular front end wall that protrudes short in the direction, and having a discharge hole for the separated liquid and a filtration screen attached to it at the rear peripheral wall of the straight body portion or the outer peripheral portion of the rear end wall. Part, and
In the screw conveyor, a supply port for the undiluted solution is provided at the back of the rotating drum near the filtrate discharge section, and a back pressure adjustment to adjust the clearance of the dewatered cake discharge to the discharge port at the front end of the bowl A centrifugal dehydrator, wherein the body is provided so as to be movable in the axial direction of the bowl. 2. The bowl according to claim 1, wherein the bowl is formed by extending a straight body having a rear end wall, followed by an inclined body having a slightly smaller diameter at a front end. Centrifugal dehydrator. 3. A bowl having a first straight body provided with a rear end wall, a short inclined body slightly tapered, and a second slightly smaller diameter than the first straight body. 2. The centrifugal dewatering apparatus according to claim 1, wherein the straight body portion is formed by providing an annular front end wall which protrudes short in the axial direction at the end. 4. The screw conveyor according to claim 1, wherein a part of a spiral blade of the screw conveyor is cut out, and a scraper blade for sludge adhering to a screen of a filtrate discharge part is provided in that part. Centrifugal dehydrator. 5. A filtrate discharge portion is provided on a rear peripheral wall of a straight body portion of the bowl and an outer peripheral portion of the rear wall, and a blade for scraping sludge adhering to a screen of the filtrate discharge portion toward a screw conveyor. The centrifugal dehydrator according to claim 1, further comprising: