JP2002273114A - Screw press having concentration function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw press divided into a concentration zone and a filtering-dehydration zone to concentrate sludge while preventing the clogging of the screen of the concentration zone and capable of dehydrating the concentrated sludge in the filtering-dehydration zone under high pressure. SOLUTION: An annular bearing is arranged between the concentration zone A and filtering-dehydration zone B of the screw press, and the outer cylinder 4a of the concentration zone A and the outer cylinder 4b of the filtering- dehydration zone B are supported on the outer peripheral part of the annular bearing and a screw shaft is divided into the concentration zone and the filtering-dehydration zone to support the screw shaft 2a of the concentration zone and the screw shaft 2b of the filtering-dehydration zone at the center part of the annular bearing to arrange the respective divided screw shafts 2a and 2b and the outer cylinders 4a and 4b in a freely rotatable manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention divides a screw press into a concentration zone and a filtration / dewatering zone to enable concentration, filtration, and dewatering of sludge having a low water load than a solid load and a low concentration. It relates to improvement of screw press.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a screw shaft 2 around which a screw blade 1 is wound is disposed on an outer cylinder 4 on which a screen 3 is stretched, and sludge supplied to a starting end side of a filtration chamber 5 is provided. A screw press is known which separates the filtrate from the screen 3 of the outer cylinder 4 while transporting the cake by the screw blade 1 and takes out the cake from the outlet 6 on the rear end side of the outer cylinder 4. Organic sludge, such as sewage, human waste, or food production processing wastewater, generates a floc by adding a polymer flocculant. These low-concentration organic sludges are concentrated in a concentrator of a centrifugal concentrator or a flotation concentrator, for example, to remove sludge having a concentration of 1% from 4 to 4.
It was concentrated to 5%, and this concentrated sludge was filtered and dewatered with a screw press. All of these devices have large installation areas, drive power costs and polymer coagulant costs are high, and maintenance is cumbersome. In addition, as a filtration and dewatering device, the filtration cylinder is divided into a sludge injection side and a discharge side in the middle part, the pitch interval of the screw blades on the sludge injection side is narrowed, and the filtration cylinder on the sludge injection side is rotated by a transfer screw. Filtration and dewatering of sludge while rotating at a speed lower than the speed, and jetting high-pressure fluid from outside the cylinder,
A screw press for washing the cake layer attached to the fine pores of the cylinder and continuously maintaining the filtration and dewatering effect is also known as described in, for example, Japanese Patent Publication No. 3-78123.

[0003]

Conventionally, sludge supplied to a screw press has a large water load than a solid matter load due to a low sludge concentration in the filtration chamber on the injection side of the thickening zone, and a large amount of sludge flows from the screen of the outer cylinder. Need to drain the water. In particular, a polymer thin film is generated by the polymer flocculant,
In the thickening zone, residues adhere to the outer cylinder screen and clogging is likely to occur.
The cake was transferred to the dewatering zone, and a weak cake was discharged without being sufficiently dewatered. And in the screw press that forcibly rotates the filtration cylinder on the sludge injection side to eliminate the clogging of the screen, the screen is prevented from being clogged by continuously injecting the washing water while rotating the outer cylinder. Although the effect can be obtained, there is a possibility that the injection water may penetrate through the fine holes of the screen and enter the inside of the outer cylinder, and the concentrated sludge may be diluted to reduce the concentration effect by half. Also, a large amount of washing water is required for continuous washing.
This invention applies the conventional technology of filtering and dewatering while rotating the outer cylinder on the sludge injection side of the screw press,
The screw press is divided into a concentration zone and a filtration / dewatering zone, and even for low-concentration organic sludge that has been agglomerated with a polymer flocculant, the sludge is concentrated while preventing clogging of the screen in the concentration zone, and this concentrated sludge is filtered. -To provide a screw press that enables high-pressure squeezing and dewatering in a dewatering zone.

[0004]

The gist of the present invention is to dispose a screw shaft around which a screw blade is wound on an outer cylinder,
The sludge supplied to the starting end of the filtration chamber is separated from the screen stretched on the outer cylinder while being conveyed by screw blades, and the filtrate is separated from the screen, and the cake is taken out from the outlet at the rear end of the outer cylinder. A ring bearing is arranged between the concentration zone of the screw press and the filtration / dehydration zone, and the outer cylinder of the concentration zone and the outer cylinder of the filtration / dehydration zone are supported on the outer periphery of the ring bearing, and the screw shaft is connected to the outer periphery of the ring bearing. Divided into a concentration zone and a filtration / dehydration zone, the screw shaft of the concentration zone and the screw shaft of the filtration / dehydration zone are supported at the center of the ring bearing, and each of the divided outer cylinders and screw shafts is rotatable. It is arranged in.

Means for rotating the outer cylinder and the screw shaft are as follows:
The screw shaft and outer cylinder of the concentration zone are linked and connected to the first drive and the first motor, and the screw shaft and outer cylinder of the filtration / dehydration zone are linked and connected to the second drive and the second motor. While rotating the outer cylinder of the zone and the screw shaft at a different speed, the number of times the screw blades slide on the screen of the outer cylinder is increased to prevent clogging of the screen while concentrating the supplied sludge with low sludge concentration, The concentrated sludge transferred is filtered and dewatered while rotating the outer cylinder and the screw shaft of the dewatering zone at different speeds. A washing tube is provided opposite to the outer cylinder of the concentration zone and the outer cylinder of the filtration / dehydration zone, and while the concentration, filtration, and dehydration are continuously performed, the outer cylinders of the concentration zone and the filtration / dehydration zone are made independent. Cleaning.

[0006] The annular bearing is divided axially by a plurality of ribs, and the annular bearing is used as a buffer zone for concentrated sludge. Coagulation supplied from the concentration zone to the filtration / dewatering zone having different rotational speeds is provided. The flock is prevented from being destroyed. If the ribs that divide the ring bearing are inclined in the torsional direction of the feed blade, the frictional resistance inside the ring bearing can be reduced. Also, if notched both ends of the rib dividing the ring bearing and separated from the blade end wound around the screw shaft of the concentration zone and dehydration zone,
The shearing action between the blades and both side surfaces of the ribs due to the rotation of the screw blades can be eliminated, and the cohesive floc can be prevented from being broken.

The outer cylinder of the concentration zone and the dewatering zone is formed in a cylindrical shape, and a tapered screw shaft is disposed in the outer cylinder, and the sludge supply side of the concentration zone and the cake discharge side of the filtration / dehydration zone are provided. Along with reducing the volume of the filtration chamber, the bearing boss of the annular bearing is formed in a tapered shape,
The screw shaft of the concentration zone supported by the bearing boss and the filter
The outer diameter of the end of the screw shaft in the dewatering zone is the same as the outer diameter of the end of the bearing boss, and from the concentration zone of the screw press to the filtration chamber where the volume has been reduced to the filtration / dewatering zone. It does not hinder the transfer of A scraper is arranged from the beginning to the end on the outer periphery of the screw blades of the concentration zone and the filtration / dehydration zone, and the scraper is elastically slidably contacted with the inner peripheral surface of the outer cylinder of the concentration zone and the filtration / dehydration zone. Because the cake layer caught on the screen of the outer cylinder is continuously scraped off with a scraper, clogging of the screen is prevented beforehand. A large amount of filtrate can be discharged without clogging.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is configured as described above, and a polymer flocculant is added to organic sludge such as sewage to cause coagulation. When the flocculated sludge is press-fitted into the filtration chamber of the concentration zone while being rotated at a high speed, the flocculated sludge discharges the filtrate from the screen of the outer cylinder and is concentrated. At the same time, the solid matter is captured on the screen of the outer cylinder to form a cake layer on the screen surface.However, the number of times the screw blades slide on the screen by the differential speed rotation is increased, and the cake layer deposited on the screen surface is reduced. Since the screw blade transfers the sludge while scraping and preventing clogging of the screen with the screw blade, even sludge having a low concentration and a large water load can be concentrated. By arranging a series of scrapers at the tip of the screw blade, clogging of the screen is prevented beforehand, and large-capacity sludge having a low concentration and a large water load can be treated. Then, the concentration ratio of the concentrated sludge supplied from the concentration zone to the filtration / dehydration zone is improved, and the supply amount of the concentrated sludge to the filtration / dehydration zone is increased.

Next, the sludge concentrated in the concentration zone of the screw press is transferred to a ring bearing, and the ring bearing serves as a buffer zone to a filtration / dewatering zone having a different rotation speed from the concentration zone. It is extruded into the outer cylinder of the filtration / dehydration zone after making it into a compacted state. The concentrated sludge further discharges the filtrate from the screen of the outer cylinder while pressurizing the blade surface of the screw blade in the latter half, and the tightening force (pressing force) of the screw blade
Filtration and dewatering are carried out by a compressing force generated from the tapered screw shaft and a presser that suppresses free discharge in discharging the cake, and the dewatered cake is discharged from the discharge port of the screw press. When supplying sludge to the screw press, the outer cylinder of the filtration / dewatering zone is provided with a differential speed from the screw shaft, and can be rotated in the same direction, in the opposite direction, or stop the outer cylinder. Although it may be, if the outer cylinder is rotated at a different speed with respect to the screw shaft, a shear force acts in a direction to peel the cake to be fixed to the screen, and it is possible to prevent the rotation, It has a kneading action and the shearing force makes the cake dewaterable.

When the dehydrated cake in the filtration chamber is filled and solidified to an excessive torque, the cake is moved in the opposite direction by rotating the outer cylinder rotating at a different speed in reverse to the screw shaft. Then, the cake that has been solidified can be loosened and softened. At the same time, if washing water is sprayed on the sliding surface of the screen and the cake, the sliding surface is lubricated and the cake is wetted at the same time to facilitate the reverse feed, eliminating the clogging of the screen, and after a certain period of time, again The processing operation can be started by rotating the outer cylinder and the screw shaft in a predetermined direction. At this time, even if the sludge is supplied to the thickening zone, the concentration is low in the sludge supply section, the filtrate is taken out from the screen drum or screen, the concentrated sludge is compacted in the buffer zone, and the solid content is reduced in a short time. Does not increase in volume. Therefore, it is possible to regenerate the screen while performing continuous operation without unnecessarily increasing the internal pressure of the filtration chamber in the filtration / dehydration zone where the filtration property is deteriorated. Also, with a screw press that operates with the outer cylinder in the filtration / dehydration zone stopped, when the screen of the outer cylinder is clogged and the filterability deteriorates,
The screen can be washed by injecting washing water into the outer cylinder while rotating the outer cylinder in the dehydration zone in the same direction while synchronizing with the screw shaft.

[0011] The dewatered cake to be discharged can easily change the filtration speed and the water content of the cake by changing the differential rotation between the outer cylinder of the filtration / dehydration zone and the screw shaft.
By reducing the differential speed rotation, the residence time in the filtration chamber is increased, and the dewatering action is remarkably performed, the water content of the cake is reduced, and high-pressure squeezing becomes possible. The screw blades transfer the sludge while preventing clogging of the screen with a scraper, so that sludge having a low concentration and a large water load can be concentrated. Increasing the differential speed increases the throughput, but also increases the water content of the cake, and eliminates clogging of the cake at the discharge section. Therefore, by adjusting the rotation speed of the outer cylinder and the screw shaft, the filtration speed and the water content of the cake are also easily changed, so that the operation with a high degree of freedom such as the low water content operation and the high capacity operation can be performed. is there.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, FIG. 1 is a partially longitudinal side view of a screw press, in which a conical screw shaft 2a is attached to a front half outer cylinder 4a.
And a cylindrical outer cylinder 4b in the latter half
And a filtration / dewatering zone B in which a conical screw shaft 2b is disposed. Screw shaft 2 of concentration zone A
The screw blades 1a and 1b are wound around the screw shaft 2b of a and the filtration / dewatering zone B, respectively, and the screens 3a and 3b are stretched over the outer cylinders 4a and 4b.
As shown in FIGS. 2 and 3, a ring bearing 7 is provided between the concentration zone A and the filtration / dehydration zone B.
In the buffer zone C, three ribs 7a divided in the axial direction are connected to an outer peripheral ring 7b and a conical bearing boss 7c at the center.
Is formed. The buffer zone C is designed to prevent the flocculation flocs supplied from the concentration zone A to the filtration / dehydration zone B having different rotation speeds from being destroyed. And filtration chamber 5a of concentration zone A and filtration / dehydration zone B,
5b is reduced in volume from the sludge supply side to the cake removal side.

As shown in FIGS. 1 and 2, the enrichment zone A
The rotary shaft 8 connected to the front end of the screw shaft 2a is supported on a bearing 10 provided on a front frame 9.
A sprocket 11 fitted on the first drive unit 12 is operatively connected to a first drive unit 12 that can rotate forward and reverse. And as shown in FIG.
A support shaft 13a connected to the rear end of the screw shaft 2a in the concentration zone A is supported by a bearing hole 7d formed in a bearing boss 7c of the ring bearing 7. A bearing 14 fitted to the front end of the outer cylinder 4a of the concentration zone A is supported by the rotating shaft 8, and the rear end of the outer cylinder 4a is attached to the end of the outer peripheral ring 7b of the annular bearing 7. It is supported. A sprocket 15 fitted to the front end of the outer cylinder 4a is interlockingly connected to a first electric motor 16 which can be rotated forward and backward, so that the screw shaft 2a and the outer cylinder 4a can be individually rotated forward and backward.

As shown in FIG. 2, a supply path 8a for the undiluted solution is formed in a rotary shaft 8 connected to the screw shaft 2a of the concentration zone A, and a supply port 8b communicating with the supply path 8a.
Are opened at the start end side of the screw shaft 2a of the filtration chamber 5a. Then, the screw shaft 2a and the outer cylinder 4a are rotated at different speeds in the same direction, or at different speeds in opposite directions to increase the number of times the screw blade 1 slides on the outer cylinder 4a,
The concentrated sludge is transferred while regenerating the screen 3a, which has a larger water load than the solid matter load and is likely to cause clogging due to residue adhesion. As shown in FIGS. 4 and 5, ribs 7a for dividing the annular bearing 7 are inclined in the twisting direction of the screw blade 1a so as to reduce the frictional resistance inside the annular bearing 7. The supply end 7e of the rib 7a that divides the annular bearing 7 is notched so as to be separated from the end of the screw blade 1a wound around the screw shaft 4a of the concentration zone A. The shearing action between the blade and the rib 7a due to the rotation is eliminated. Then, the concentrated sludge transferred from the concentration zone is extruded into the filtration / dewatering zone B while keeping the concentrated sludge in a compact state while preventing the destruction of the flocculated floc.

As shown in FIGS. 1 and 2, a drive shaft 17 connected to a rear end of the screw shaft 2b of the filtration / dewatering zone B is supported by a bearing 19 of a rear frame 18.
A support shaft 13b provided at the tip of the screw shaft 2b is supported by a bearing hole 7d of the annular bearing 7. A sprocket 20 fitted on the drive shaft 17 is operatively connected to a second drive unit 21 that can rotate forward and reverse. The outer cylinder 4 of the filtration / dehydration zone B
The front end of b is supported on the end of the outer peripheral ring 7b of the ring bearing 7, and the rotary plate bearing 22 fixed to the rear end of the outer cylinder 4b is supported by the machine frame 23. A sprocket 24 fitted to the rear end of the outer cylinder 4b is operatively connected to a second electric motor 25 that can rotate forward and reverse. Then, the screw shaft 2b and the outer cylinder 4b of the filtration / dehydration zone B are individually disposed so as to be capable of normal and reverse rotation, and the outer cylinder 4b of the filtration / dehydration zone B is rotated at a different speed in the same direction as the screw shaft 2b. Alternatively, filtration and dehydration can be performed while rotating at a different speed in the opposite direction.

As shown in FIG. 3, an end 7e on the discharge side of a rib 7a for dividing the ring bearing 7 is also notched.
It is separated from the end of the screw blade 1b wound around the screw shaft 2b of the filtration / dewatering zone B, and prevents the cohesive floc from being destroyed except for the shearing action between the blade and the side surface of the rib 7a due to the rotation of the screw blade 1b. I can do it. And the screw shaft 2 of the filtration / dehydration zone B
b and the outer cylinder 4b are rotated at a different speed in the same direction as the screw shaft 2b, or are rotated at a different speed in the opposite direction so that filtration and dehydration can be performed.
Of the concentrated sludge extruded from the screen 3b acts on the screen 3b in the direction of peeling the cake to be adhered to the screen 3b, thereby preventing the sludge from rotating. The speed difference has a kneading effect, and the shear force makes the cake dewaterable. When the dehydrated cake in the filtration chamber 5b fills and solidifies to an excessive torque, the outer cylinder 4 rotating at a differential speed
If b is rotated in the opposite direction with respect to the screw shaft 2b, the cake moves to the sludge supply side and the filled cake can be loosened and softened.

As shown in FIG. 1, the outer cylinder 4 of the concentration zone A
a and a washing pipe 26 around the outer cylinder 4b of the filtration / dehydration zone B.
When the screens 3a and 3b of the outer cylinders 4a and 4b are clogged, washing water is injected to the outer cylinder 4a or the outer cylinder 4b on the clogged side. The screens 3a and 3b and the sliding surface of the cake are lubricated and the cake is moistened at the same time to facilitate the reverse feeding, and the clogging of the screens 3a and 3b is eliminated. The processing operation can be started by rotating in a predetermined direction. At this time, even if the sludge is supplied to the concentration zone, the concentration is low in the sludge supply section, the filtrate is taken out from the screen 3a of the outer cylinder 4a, and the concentrated sludge is compacted in the buffer zone. The volume of solid content does not increase. Therefore, the screen 3b can be regenerated while the continuous operation is being performed without increasing the internal pressure of the filtration chamber 5b in the filtration / dehydration zone where the filtration property is deteriorated.

As shown in FIG. 6, the screw blade 1a in the concentration zone A and the screw blade 1 in the filtration / dewatering zone B
A series of scrapers 27a, 27b having elasticity such as rubber are fixed to the tip of the screw blade 1a, 1b from the beginning to the end of the screw blades 1a, 1b with bolts 28 and nuts 29. Outer cylinder 4 of zone B
The inner peripheral surfaces of a and 4b are slidably contacted with each other. And
The filtrate is separated from the screen 3a of the outer cylinder 4a in which clogging is prevented by the scraper 27a in the concentration zone A,
The sludge supply amount in the concentration zone A is increased, and the cake layer of the screen 3b of the outer cylinder 4b is scraped off by the scraper 27b in the filtration / dewatering zone B for supplying the concentrated sludge, thereby performing high dehydration while preventing clogging. It is like that. In addition,
The outer cylinder 4b of the filtration / dehydration zone B may be stopped, and may be rotated when the filterability deteriorates. A presser 30 is provided opposite to the discharge port 6 on the end side of the outer cylinder 4b. The air cylinder 31 connected to the rear end of the presser 30 applies back pressure to the cake while controlling the opening amount of the discharge port 6. Is adjusted.

[0019]

The present invention is configured as described above,
The screw press is divided into a concentration zone and a filtration / dewatering zone. By adjusting the rotation speed of the outer cylinder and the screw shaft, both the filtration speed and the water content of the cake can be easily changed, reducing the water content and increasing the capacity. Thus, the operation with a high degree of freedom becomes possible, and the optimal operation of the concentration zone and the filtration / dehydration zone becomes possible for organic sludge of various kinds and various properties. That is, in the conventional apparatus that continuously injects washing water while rotating the outer cylinder on the sludge injection side, the injected water enters the outer cylinder, reduces the concentration effect by half, and requires much washing water. However, in the present invention, the annular bearing is disposed between the concentration zone and the filtration / dehydration zone of the screw press, and the divided outer cylinders and the screw shaft are rotatably disposed. In addition, the number of revolutions of the screw blades in the concentration zone can be relatively increased, and the filtration surface of the screen can be regenerated to increase the concentration of the sludge transferred to the filtration / dewatering zone. Then, since the outer cylinder of the filtration / dehydration zone is rotated at a differential speed with respect to the screw shaft, the cake to be adhered to the screen is peeled off, and a shear force acts to prevent rotation.

Since a ring bearing is disposed between the concentration zone and the filtration / dehydration zone as a buffer zone, the buffer zone is provided for the filtration / dehydration zone having a different rotation speed from that of the concentration zone. It can be extruded into the outer cylinder of the filtration / dehydration zone. And, since both ends of the rib dividing the ring bearing were separated from the blade end of the screw blade in the concentration zone and the dewatering zone, the soft coagulated sludge was not destroyed under the influence of the screw blade, Dehydration is not impaired. In addition, since the washing pipe is provided opposite to the outer cylinder of the concentration zone and the outer cylinder of the filtration / dehydration zone, the outer cylinder of the concentration zone and the filtration / dehydration zone are made independent while performing the concentration, filtration and dehydration continuously. It can be washed. In addition, the scraper can be
Sliding contact with the inner peripheral surface of the outer cylinder of the dewatering zone prevents clogging of the screen beforehand, and enables a large amount of filtrate to be discharged without clogging even with sludge having a low concentration and a large water load.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a screw press having a concentration function according to the present invention.

FIG. 2 is a vertical sectional side view of a main part of the screw press according to the present invention.

FIG. 3 is a longitudinal sectional view of the annular bearing in the buffer zone.

FIG. 4 is a front view of the ring bearing.

FIG. 5 is a side view of the ring bearing.

FIG. 6 is a schematic side view of the scraper fixed to the screw blade.

FIG. 7 is a schematic side view of a conventional screw press.

[Explanation of symbols]

 1, 1a, 1b Screw blade 2, 2a, 2b Screw shaft 3, 3a, 3b Screen 4, 4a, 4b Outer cylinder 5, 5a, 5b Filtration chamber 6 Outlet 7 Ring bearing 7a Rib 7c Bearing boss 7e End 12 First motor 16 First motor 21 Second motor 25 Second motor 26a, 26b Washing pipe 27a, 27b Scraper A Concentration zone B Filtration / dewatering zone C Buffer zone

Claims (8)

[Claims] 1. A screw shaft (2) around which a screw blade (1) is wound is disposed on an outer cylinder (4), and sludge supplied to a starting end side of a filtration chamber (5) is passed through the screw blade (1). In the screw press, the filtrate is separated from the screen (3) stretched over the outer cylinder (4) while being conveyed, and the cake is taken out from the outlet (6) at the rear end of the outer cylinder (4). A ring bearing (7) is arranged between the concentration zone A and the filtration / dehydration zone B, and the outer cylinder (4a) of the concentration zone A
And the outer cylinder (4b) of the filtration / dewatering zone B with a ring bearing (7)
And the screw shaft (2) is divided into a concentration zone A and a filtration / dewatering zone B, and a screw shaft (2a) of the concentration zone A and a screw shaft (2b) of the filtration / dewatering zone B Are supported at the center of the ring bearing (7), and the divided screw shafts (2a, 2b)
A screw press having a concentrating function, wherein the screw press and the outer cylinder (4a, 4b) are rotatably arranged. 2. The screw shaft (2) of the concentration zone A
a) and the outer cylinder (4a) are operatively connected to the first drive unit (12) and the first electric motor (16), and the filtration / dewatering zone B
The screw press having a condensing function according to claim 1, wherein the screw shaft (2b) and the outer cylinder (4b) are connected to the second driving device (21) and the second electric motor (25) in an interlocking manner. 3. A washing pipe (26a, 26a) is provided in the outer cylinder (4a) of the concentration zone A and the outer cylinder (4b) of the filtration / dehydration zone B.
The screw press having a concentration function according to claim 1 or 2, wherein b) is provided opposite to the screw press. 4. The ring bearing (7) is connected to a plurality of ribs (7a).
The screw press having a condensing function according to any one of claims 1 to 3, wherein the ring bearing (7) is divided into buffer zones C for the condensed sludge. 5. A screw press having a condensing function according to claim 4, wherein the rib (7a) for dividing the annular bearing (7) in the axial direction is inclined in the twisting direction of the feed blade. . 6. A rib (7) for dividing said annular bearing (7).
Notch both ends (7e, 7e) of a), and screw shafts (2a, 2b) of concentration zone A and filtration / dewatering zone B
The screw press having a condensing function according to claim 4 or 5, characterized in that the screw press (1a, 1b) wound around is separated from the blade end. 7. The concentration zone A and the filtration / dehydration zone B
The outer cylinders (4a, 4b) are formed in a cylindrical shape,
a, 4b) with tapered screw shafts (2a, 2b)
And the filtration chambers (5a, 5a, 5a, 5a) from the sludge supply side of the concentration zone A to the cake discharge side of the filtration / dewatering zone B.
b), the bearing boss (7c) of the ring bearing (7) is formed in a tapered shape, and the bearing boss (7) is formed.
The outer diameter of the end of the screw shaft (2a) of the concentration zone A and the end of the screw shaft (2b) of the filtration / dehydration zone B which are supported in c) are the same as the outer diameter of the end of the bearing boss (7c). The screw press having a concentration function according to any one of claims 1 to 6, wherein 8. The concentration zone A and the filtration / dehydration zone B
Scrapers (27a, 27b) are arranged on the outer periphery of the screw blades (1a, 1b) from the start end to the end.
The scraper (27a, 27b) is elastically slidably brought into contact with the inner peripheral surface of the outer cylinder (4a, 4b) of the concentration zone A and the filtration / dewatering zone B. A screw press having a concentrating function as described in Item.