JP2001145810A - Solid-liquid separation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-liquid separation apparatus in which a rotation screen is prevented from being clogged and leakage of SS is prevented. SOLUTION: A rotation screen 4 is composed by reciprocally layering a plurality of ring-like rotation plates 17 and of ring-like movable plates 18 in the axial direction, a screw conveyer 5 is concentrically arranged in the inside of the rotation screen 4, a rotation plate block 22 is composed by unitedly joining the respective plates 17 with fixing rods 22, and a rotation plate operation apparatus 24 for rotating the rotation plate block 22 is installed separately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-liquid separation device used for solid-liquid separation of sewage sludge and the like.

[0002]

2. Description of the Related Art Conventionally, there is a screw type filtration device as a device for solid-liquid separation of sewage sludge and the like. In this screw-type filtration device, a screw conveyor is arranged coaxially inside a cylindrical rotary screen, and the rotary screen is formed by laminating a plurality of ring-shaped filtration plates in the axial direction. The sludge is put into the inside from one end side of the rotating screen, and is condensed and dewatered while being axially fed by a screw conveyor, and is filtered by the rotating screen. The filtered filtrate is discharged through a minute gap formed between the filtration plates of the rotating screen, and the dewatered sludge is discharged from the other end of the rotating screen.

[0003]

In the above construction, the condensed and dewatered dewatered sludge is conveyed in the axial direction of the rotating screen by the screw conveyor, but is conveyed to the gap between the outer peripheral edge of the screw and the inner peripheral surface of the rotating screen. There is a problem that sludge remains in a layer and causes clogging. For this purpose, there is a rotating screen formed by alternately laminating a plurality of ring-shaped filtration plates and movable plates in the axial direction to form a rotating screen. Is formed smaller in diameter than the outer diameter of the screw.

In this configuration, the outer peripheral edge of the screw comes into contact with a part of the inner peripheral edge of the movable plate, so that the movable plate is pressed in the radial direction with the rotation of the screw to slide, and thereby the rotary screen of the rotary screen is rotated. Sludge attached to the inner peripheral surface is pushed out in the radial direction to prevent clogging.
However, when the movable plate slides in the radial direction, the sliding causes a gap S between the filtration plate and the movable plate.
As the amount of S (suspended material) leaks in the radial direction and the amount of sliding of the movable plate increases, the amount of leakage of SS that leaks from the gap between the filtration plate and the movable plate increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to prevent the rotating screen from being clogged,
It is an object of the present invention to provide a solid-liquid separation device capable of preventing leakage of S.

[0006]

According to a first aspect of the present invention, there is provided a solid-liquid separator according to the first aspect of the present invention, wherein a plurality of ring-shaped rotating plates and a movable plate are alternately stacked in the axial direction. A rotary plate driving device for forming a rotary screen, forming a rotary plate block by connecting a screw conveyor coaxially inside the rotary screen, integrally connecting each rotary plate with a fixed rod, and rotating the rotary plate block Are provided separately.

[0007] With the above construction, sludge is introduced into the inside from one end of the rotating screen, dewatered while being conveyed in the axial direction by a screw conveyor, and filtered by the rotating screen. The filtered filtrate is discharged through a minute gap formed between the rotating plate and the movable plate of the rotating screen, and the dewatered sludge is discharged from the other end of the rotating screen.

In this dewatering operation, the rotating plate driving device forcibly rotates the rotating plate block at a rotation speed different from that of the screw conveyor,
A rotational speed difference is generated between the movable plate and the rotating plate that rotate according to the rotation of the screw conveyor. Due to this difference in rotation speed, a shearing force acts in the rotating direction between the sludge layer adhering to the inner peripheral surface of the movable plate and the sludge layer adhering to the inner peripheral surface of the rotating plate, and the adhered sludge is peeled off. Clogging is prevented.

The relative movement (sliding) between the rotating plate and the movable plate occurs in the circumferential direction around the axis and does not occur in the radial direction, so that the SS does not leak from the screen formed by the minute gap between the plates. Since the rotation direction and rotation speed of the rotating plate block can be set regardless of the rotation speed of the screw, the operation can be performed according to the sludge properties and the target dewatering performance.

[0010] The solid-liquid separation device of the present invention according to claim 2 comprises:
On the inner peripheral surface of the movable plate, a projection is provided which is engaged with the outer peripheral edge of the screw of the screw conveyor in the circumferential direction and slidably contacts in the axial direction. With the above-described configuration, the movable plate reliably rotates at a predetermined rotation speed according to the rotation speed of the screw conveyor as the screw conveyor rotates, so that the rotation speed difference between the rotation plate and the movable plate can be increased to an arbitrary speed difference. It can be controlled with high precision.

[0011] The solid-liquid separation device of the present invention according to claim 3 comprises:
The rotating plate block is divided into a plurality of blocks in the axial direction, and a rotating plate driving device is provided for rotating each of the divided blocks at a different rotation speed. In the above-described configuration, the sludge moves in the axial direction in the rotary screen while being condensed and dewatered by the screw conveyor. As the dewatering proceeds, the viscosity of the sludge increases, and the sludge is hardly peeled off from the rotary plate and the movable plate. For this reason, the rotational speed of each divided block divided in the axial direction is made different, and as the dewatered sludge approaches the discharge side of the rotary screen, the rotational speed difference between the rotary plate and the movable plate is increased, thereby increasing the shearing force. Promotes sludge separation. It is also possible to rotate in different directions for each divided block.

The solid-liquid separation device according to the present invention according to claim 4 is
At least one of the rotating plate and the movable plate is formed to be thinner as the closer to the sludge input side of the rotating screen. In the above configuration, the sludge moves in the axial direction in the rotating screen while being condensed and dewatered by the screw conveyor. At this time, the amount of desorbed liquid is large at the beginning of dehydration, and the amount of desorbed liquid decreases as dehydration proceeds. For this reason, the thickness of the plate is formed thinner as it is closer to the sludge input side of the rotating screen, and the number of screens formed by the minute gap between the rotating plate and the movable plate is reduced in the axial direction by the sludge loading of the rotating screen. By increasing the number toward the side, drainage of the desorbed liquid is facilitated and dehydration efficiency is increased.

[0013] The solid-liquid separation device of the present invention according to claim 5 comprises:
The width of the screen formed by the minute gap between the rotating plate and the movable plate is narrower as the screen is closer to the sludge discharge side of the rotating screen. In the above configuration, the sludge moves in the axial direction in the rotary screen while being condensed and dewatered by the screw conveyor, and the pressure density increases with the progress of dehydration. Therefore, the SS component is more likely to leak toward the sludge discharge side of the rotary screen. For this reason, the width of the screen is narrower as the screen is closer to the sludge discharge side of the rotating screen, thereby preventing leakage of SS.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4, a solid-liquid separation device 1 has a sludge input section 2 for inputting sludge on one side, and a sludge discharge section 3 for discharging dehydrated sludge on the other side. A rotating screen 4 is arranged between the discharge sections 3,
A screw conveyor 5 is disposed coaxially inside the rotating screen 4.

The sludge feeding section 2 has a sludge feeding port 6 at an upper portion thereof, holds a rotating shaft 8 of a screw 7 of a screw conveyor 5 rotatably via a bearing 9, and connects one end of the rotating screen 4 to a bearing 10. It is rotatably held through The pitch of the screw 7 of the screw conveyor 5 is reduced as the pitch is closer to the sludge discharge section 3. The pitch of the screw 7 can be made constant and the screw shaft can be made thicker as it approaches the sludge discharge section 3.

The sludge discharge section 3 has a built-in back pressure plate 11 fixed to the rotating shaft 8, has a sludge discharge port 12 at the lower end, and rotatably holds the rotating shaft 8 via a bearing 13. The other end of the rotating screen 4 is rotatably held via a bearing 14. A conveyor drive motor 16 is connected to the rotating shaft 8 via a gear train 15 having a predetermined reduction ratio.
The rotating screen 4 is formed by alternately stacking a plurality of ring-shaped rotating plates 17 and movable plates 18 in the axial direction. Spacers 19 are arranged between the rotating plates 17 and the rotating plates 17 and end plates are provided on both sides. The rotating plate block 22 is formed by integrally connecting the end plates 20 and the rotating plate 17 with the fixed rods 21. A plate drive motor 24 is connected to one end plate 20 via a gear train 23 having a predetermined reduction ratio.

As shown in FIG. 2, the rotating plate 17 has a plurality of connecting portions 25 on the outer peripheral edge, and each connecting portion 25 has a through hole 26 through which the fixed rod 21 is inserted.
As shown in FIG. 3, the movable plate 18 has a radially projecting protrusion 27 on the inner peripheral surface, the protrusion 27 circumferentially engages with the outer peripheral edge of the screw 7 of the screw conveyor 5, and has an axial line. Sliding contact in the direction.

With the above configuration, during operation, the conveyor drive motor 16 is driven to rotate the rotating shaft 8 and the screw 7, and the plate drive motor 24 is driven to rotate the rotary screen 4. Screw conveyor 5
The rotation speed of the rotating screen 4 and the rotation speed of the rotating screen 4 are adjusted in advance by a reduction ratio or the like, and are set for each season according to sludge properties such as a water content.

The sludge is supplied from the sludge inlet 6 to the sludge inlet 2 and is rotated by the screw conveyor 5 on the rotating screen 4.
Into the inside from one end side. Screw this sludge to screw 7
Is pressed in the axial direction of the rotating shaft 8 by the rotation of the rotary shaft 8, the dewatered sludge is discharged from the other end of the rotating screen 4, and the desorbed liquid is discharged between the rotating plate 17 and the movable plate 18 of the rotating screen 4. It is discharged through a screen formed by the minute gap and filtered by the rotating screen 4.

In this dewatering operation, the rotating plate block 22 is forcibly rotated at a rotation speed different from that of the screw conveyor 5. As a result, the movable plate 18 that engages with the screw 7 at the protrusion 27 rotates at a predetermined rotation speed in accordance with the rotation of the screw conveyor 5, and a rotation speed difference is generated between the movable plate 18 and the rotation plate 17. Let it. The rotation speed difference causes the sludge layer adhering to the inner peripheral surface of the movable plate 18 and the rotating plate 17 to rotate.
A shearing force acts in the rotating direction between the sludge layers adhering to the inner peripheral surface of the substrate, and the adhering sludge layer is peeled off to prevent clogging.

Rotating plate 17 and movable plate 18
Relative movement (sliding) occurs in the circumferential direction around the axis and does not occur in the radial direction, so that SS does not leak from the screen formed by the minute gap between the plates.
The rotation direction and rotation speed of the rotary plate block 22 can be set irrespective of the rotation speed of the screw conveyor 5, so that operation in accordance with sludge properties and target dewatering performance is possible. The engagement between the projection 27 and the screw 7 ensures that the movable plate 18 rotates at a predetermined rotation speed in accordance with the rotation speed of the screw 7 with the rotation of the screw conveyor 5. The rotational speed difference can be controlled to an arbitrary speed difference with high accuracy. In the present embodiment, the movable plate 1
Although the shape 8 has the protrusion 27, it can be formed in a simple ring shape without the protrusion 27.

The sludge moves axially inside the rotary screen 4 while being condensed and dewatered by the screw conveyor 5,
As the dehydration proceeds, the viscosity of the sludge increases, and it becomes difficult to separate the sludge from the rotating plate 17 and the movable plate 18. For this reason, a rotating plate block 22 is formed by dividing the rotating plate 17 into an appropriate number of rotating plates 17, and a power transmission mechanism for rotating and driving each divided block at a different rotation speed is provided between each divided block and the plate drive motor 24. It is also possible to provide the dewatered sludge as the dewatered sludge approaches the discharge side of the rotating screen 4 to increase the rotational speed difference between the rotating plate 17 and the movable plate 18 to increase the shearing force and promote the separation of the sludge. It is also possible to rotate the divided blocks alternately in opposite directions.

The sludge moves in the axial direction inside the rotary screen 4 while being condensed and dewatered by the screw conveyor 5,
At the beginning of the dehydration, the amount of the desorbed liquid is large, and as the dehydration proceeds, the amount of the desorbed liquid decreases. For this reason, the thickness of at least one of the rotating plate 17 and the movable plate 18 can be made thinner as the rotating screen 4 is closer to the sludge input unit 2 side of the rotating screen 4.

For example, in the schematic diagram shown in FIG. 4, each rotating plate 17 is formed so that the thicknesses Ta1, Ta2, Ta3, and Ta4 of each rotating plate 17 have a relationship of Ta1>Ta2>Ta3> Ta4. Alternatively, each rotating plate 17 is formed such that the thicknesses Tb1, Tb2, Tb3, and Tb4 of each movable plate 18 have a relationship of Tb1>Tb2> Tb3. Alternatively, the above relationships are simultaneously realized.

As a result, the number of screens formed by the minute gap between the rotating plate 17 and the movable plate 18 increases in the axial direction toward the sludge introduction section 2 of the rotating screen 4, and the desorbed liquid is discharged. And the dewatering efficiency is improved. The sludge moves in the axial direction inside the rotary screen 4 while being condensed and dewatered by the screw conveyor 5, and the pressure density increases with the progress of dehydration. Therefore, the SS component tends to leak toward the sludge discharge part 3 of the rotary screen 4. Become.

For this reason, the width of the screen formed by the minute gap between the rotating plate 17 and the movable plate 18 can be made narrower as the rotating screen 4 is closer to the sludge discharge portion 3 side. . For example, in the schematic diagram shown in FIG. 4, the widths Tc1, Tc2,
Tc3 and Tc4 are defined as Tc1 <Tc2 <Tc3 <Tc4 <T
The rotating plates 17 and the movable plates 18 are arranged so as to have a relationship of c5.

[0027] With this, the width of the screen is narrower as the width of the screen is closer to the side of the sludge discharge section 3 of the rotating screen 4, thereby preventing leakage of SS.

[0028]

As described above, according to the present invention, a moving speed difference is generated between a movable plate that rotates in accordance with a screw conveyor and a rotating plate that is forcibly and separately driven to rotate, thereby enabling the movable plate to rotate. By applying a shearing force in the rotating direction between the sludge layer adhering to the inner peripheral surface of the plate and the sludge layer adhering to the inner peripheral surface of the rotating plate, the adhering sludge can be peeled off to prevent clogging. Since the rotating plate and the movable plate do not slide in the radial direction but relatively move in the circumferential direction around the axis, the SS does not leak from the screen formed by the minute gap between the plates. The rotational speed of each divided block divided in the axial direction is made different, and as the dewatered sludge approaches the discharge side of the rotating screen, the rotational speed difference between the rotating plate and the movable plate is increased, so that the shearing force is strengthened and the sludge is removed. Peeling can be promoted. By increasing the number of screens formed by the minute gaps between the rotating plate and the movable plate toward the sludge input side of the rotating screen in the axial direction, it is possible to easily discharge the desorbed liquid and increase the dewatering efficiency. . By forming the screen width narrower as the screen is closer to the sludge discharge side of the rotating screen, leakage of SS can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a solid-liquid separation device according to an embodiment of the present invention.

FIG. 2 is a front view of the rotating plate according to the embodiment.

FIG. 3 is a front view of a movable plate according to the embodiment.

FIG. 4 is a schematic diagram showing a positional relationship between a rotating plate and a movable plate in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid-liquid separation apparatus 2 Sludge input part 3 Sludge discharge part 4 Rotary screen 5 Screw conveyor 6 Sludge input port 7 Screw 8 Rotary shaft 9, 10, 13, 14 Bearing 11 Back pressure plate 12 Sludge discharge port 15 Gear train 16 Conveyor drive motor Reference Signs List 17 rotating plate 18 movable plate 19 spacer 20 end plate 21 fixed rod 22 rotating plate block 23 gear train 24 plate drive motor 25 connecting part 26 through hole 27 protrusion

Claims (5)

[Claims] 1. A rotating screen is formed by alternately laminating a plurality of ring-shaped rotating plates and a movable plate in the axial direction, and a screw conveyor is coaxially arranged inside the rotating screen to fix each rotating plate. A solid-liquid separator, wherein a rotary plate block is formed by integrally connecting with a rod, and a rotary plate driving device for rotating the rotary plate block is separately provided. 2. The projection according to claim 1, wherein a projection is provided on an inner peripheral surface of the movable plate, the projection being engaged with an outer peripheral edge of a screw of the screw conveyor in a circumferential direction and slidingly contacting in an axial direction. Solid-liquid separation device. 3. The rotating plate drive device according to claim 1, wherein the rotating plate block is divided into a plurality of blocks in the axial direction, and a rotating plate driving device that rotates each of the divided blocks at a different rotation speed is provided. Solid-liquid separation device. 4. The apparatus according to claim 1, wherein at least one of the rotating plate and the movable plate has a smaller thickness as the rotating screen is closer to the sludge input side of the rotating screen. 3. The solid-liquid separation device according to item 1. 5. The screen according to claim 1, wherein the width of the screen formed by the minute gap between the rotating plate and the movable plate is narrower as the screen is closer to the sludge discharge side of the rotating screen. Item 2. The solid-liquid separation device according to item 1.