JPH1099724A - Centrifugal thickener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To feed liquid to be treated to a strongest portion of a centrifugal force in a treating space, to allow the solids to settle and to make efficiency remarkably high without requiring to impart excessive rotational speed by constituting the liquid to be treated so as to be fed into the treating space in the vicinity of the inside surface of an outer cylinder. SOLUTION: Suspension liquid is fed into the treating space 5 between the outer cylinder 1 and the inner cylinder 2 through a liquid flow path 4 of a hollow rotary shaft and is affected strong centrifugal force by high speed rotation of the inner and outer cylinders 2, 1. Thus, the solids settle on the inside surface of the outer cylinder 1, become condensed sludge, are conveyed with a screw blade 3 and discharged from a discharge port 6 at one end of the outer cylinder 1. Separated liquid settled the solids and became clarified liquid is discharged from a discharge port 7. In this case, because a feed disk 8 is arranged at the tip 4' of the liquid flow path 4, the liquid to be treated is guided to the inside surface of the outer cylinder 1 along the feed disk 8, and certainly passes through a portion under the strongest centrifugal force and while it is affected by a sufficient settling force, enters the treating space 5 and further here receives the settling force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw decanter-type centrifugal concentrator used for separating a solid suspension from fine solids by solid-liquid separation by centrifugal force.

[0002]

2. Description of the Related Art In a horizontal screw decanter type centrifugal concentrator of this type, an inner cylinder is provided coaxially in an outer cylinder rotating at a high speed, and a screw is formed on the outer surface of the inner cylinder so as to leave a slight gap with the inner surface of the outer cylinder. A blade is provided, and the inner and outer cylinders are rotated in the same direction with a speed difference. The suspension as the liquid to be treated is supplied to the treatment space formed between the outer cylinder and the inner cylinder through the rotation shaft, and receives a strong centrifugal force due to the high-speed rotation of the inner and outer cylinders. For this reason, the solids settle on the inner surface of the outer cylinder and become concentrated sludge,
It is transferred by the screw blades and discharged from the discharge port at one end of the outer cylinder. On the other hand, the separated liquid in which the solid content has settled and turned into a clear liquid is discharged from near the liquid level in the processing space.

[0003]

In the above-described screw decanter type centrifugal concentrator, the suspension is fed into the processing space from near the surface of the inner cylinder. However, the centrifugal force is proportional to the radius and is large on the inner surface of the outer cylinder, and smaller on the surface of the inner cylinder or at the liquid level near the inner cylinder surface. For this reason, the liquid to be treated heading toward the separated liquid discharge port along the liquid surface is discharged through a space having a small centrifugal force. In order to sufficiently sediment solids from the liquid to be processed flowing through the space with a small centrifugal force, the liquid to be processed near the inner surface of the outer cylinder must be given a high-speed rotation that generates an excessive centrifugal force. No. For this reason, to give high speed rotation to the inner and outer cylinders,
Excessive driving force is required to transfer the sludge that has been partially compacted due to excessive centrifugal force on the inner surface of the outer cylinder.
An object of the present invention is to provide a screw decanter-type centrifugal concentrator that does not have such a problem.

[0004]

A screw decanter-type centrifugal concentrator according to the present invention is characterized in that a liquid to be processed is fed into the processing space near the inner surface of an outer cylinder. The liquid to be treated is usually supplied through the rotating shaft of the inner and outer cylinders, but extends the supply flow path to near the inner surface of the outer cylinder. The extended supply passage may be a pipe extending to the inner surface of the outer cylinder communicating with the flow path of the rotary shaft, or may be formed by a feed disk extending from the inner cylinder surface to the vicinity of the outer cylinder inner surface. This feed disk is provided at one end of the inner cylinder in a so-called concurrent centrifuge which is supplied from one end of the outer cylinder and discharged from the other end. In a counter current type centrifugal separator in which the liquid and the separated liquid are discharged in opposite directions, they are disposed before and after the supply hole. Desirably, the feed disk has guide vanes extending substantially in the radial direction. In a countercurrent centrifugal concentrator, the feed disk penetrates the feed disk near the inner cylinder surface and rotates the inner cylinder. A passage for the liquid to be treated may be provided in the axial direction.

[0005]

In the centrifugal concentrator of the present invention having the above structure, the liquid to be treated is supplied to the portion of the processing space having the largest centrifugal force, and fine particles or solids having a small specific gravity difference are immediately settled by the large centrifugal force. There is no danger of being separated and separated by the flow of the separated liquid in the direction of the liquid surface, so that the separated liquid is again wound up and raised. For this reason, it is not necessary to give an excessively high rotation speed, and the concentration of the concentrated sludge on the inner surface of the outer cylinder becomes excessively high due to the excessive centrifugal force, and a large driving force is not required for the transfer.

[0006]

Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of a screw decanter type centrifugal concentrator of a concurrent type, wherein 1 is an outer cylinder rotating at a high speed, 2 is an inner cylinder provided coaxially therein, and the outer surface of the inner cylinder is provided on the outer surface of the inner cylinder. The screw blade 3 is provided so as to leave a slight gap with the inner surface of the cylinder, and the inner and outer cylinders are rotated in the same direction with a speed difference. The suspension, which is the liquid to be treated, passes through the liquid flow path 4 formed on the hollow rotating shaft.
It is supplied to the processing space 5 formed between the outer cylinder and the inner cylinder, and receives a strong centrifugal force due to the high-speed rotation of the inner and outer cylinders. For this reason, the solids settle on the inner surface of the outer cylinder and become concentrated sludge,
It is transferred by the screw blade 3 and discharged from the discharge port 6 at one end of the outer cylinder 1. On the other hand, the separated liquid in which the solid content has settled and has become a clear liquid is discharged from the discharge port 7. In the conventional centrifugal concentrator, the front end 4 ′ of the liquid flow path 4 is directly opened to the processing space 5, and the liquid to be processed flows from the front end 4 ′ to the processing space 5.
Supplied to In the centrifugal concentrator according to the present invention, the feed disk 8 is disposed at the opening of the liquid flow path. The liquid to be processed from the liquid flow path 4 is blocked by the feed disk 8 and cannot spread into the processing space 5, is guided along the feed disk 8 to the inner surface of the outer cylinder 1, and It enters the processing space 5 through the gap of the outer cylinder 1. For this reason, the liquid to be treated always passes through the portion having the highest centrifugal force, and the fine solids and solids having a small difference in specific gravity enter the processing space 5 while receiving a sufficient sedimentation force, and further undergo a sedimentation action. Will be.

FIG. 2 shows a longitudinal sectional view of a portion A of FIG. 1 and a transverse sectional view of the portion along BB in another embodiment. In this embodiment, the liquid flow path 4 extends to the vicinity of the inner surface of the outer cylinder 1 while keeping its pipe shape, and supplies the liquid to be treated from its tip 4 ′. In this way, the liquid to be processed is forcibly given the same rotational speed as the inner cylinder 2 by the liquid flow path 4, and it is guaranteed that a strong centrifugal force acts. In the structure of this embodiment, the liquid to be treated is supplied to the processing space at the intermediate portion of the inner cylinder 2, and the concentrated liquid and the separated liquid are discharged from the discharge ports provided at the opposite ends of the outer cylinder 1, respectively. It can be used as it is for a counter current type centrifugal concentrator.

In the embodiment shown in FIG. 3, a guide vane 9 extending in the radial direction is provided on the feed disk 8 of the first embodiment as shown in a transverse sectional view (b) of FIG. Things. With this guide vane, high-speed rotation can be given to the liquid to be treated, as in the embodiment of FIG.

FIG. 4 shows an example in which feed disks 8 and 8 'are provided in a counter current type centrifugal concentrator.
The liquid to be treated is supplied from a liquid supply hole 4 'at an intermediate portion of the inner cylinder 2. In the centrifugal concentrator according to the present invention, feed disks 8, 8' are disposed before and after the liquid supply hole 4 '. The liquid to be processed is supplied into the processing space 5 from the gap between the tip of the feed disk and the inner surface of the outer cylinder 1. If necessary, the diameter of the feed disk 8 ′ may be smaller than the diameter of the feed disk 8. FIG. 5 is an example in which guide vanes 9 are provided on the feed disk 8.

In the above embodiment of the centrifugal concentrator of the countercurrent type, the flow of the liquid from the discharge side of the concentrate to the discharge side of the separated liquid along the inner cylinder 2 is blocked by the feed disk 8. If the separated liquid stays along the inner cylinder 2 on the discharge side of the concentrated liquid due to the nature of the suspension, a flow path penetrating the feed disks 8 and 8 ′ along the inner cylinder 2 can be provided. . FIG. 6 shows a cross-sectional view corresponding to a cross-sectional view taken along the line DD of the embodiment shown in FIG. 5, and FIG. 7 shows a vertical cross-sectional view taken along the line EE of FIG. Shown in In this example, a flow path 10 for the separated liquid is provided along the surface of the inner cylinder 2 and penetrating the feed disks 8 and 8 '.

[0011]

According to the screw decanter type centrifugal concentrator of the present invention, the liquid to be processed is supplied to the portion of the processing space where the centrifugal force is strongest, and the solid content is settled. An extremely efficient centrifugal concentrator can be obtained. According to the experiment, in the centrifugal concentrator having the conventional structure, a solid content recovery rate of 90% was obtained by applying a centrifugal force of 1000 g. Thus, a recovery rate of 90% or more could be stably obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the structure of an embodiment of a screw decanter-type concurrent centrifugal concentrator according to the present invention.

FIG. 2 is a partial longitudinal sectional view and a transverse sectional view of another embodiment of the screw decanter type cocurrent centrifugal concentrator according to the present invention.

FIG. 3 is a partial longitudinal sectional view and a transverse sectional view of still another embodiment of the screw decanter-type concurrent centrifugal concentrator according to the present invention.

FIG. 4 is a longitudinal sectional view showing the structure of one embodiment of a screw decanter type counter current centrifugal concentrator according to the present invention.

FIG. 5 is a longitudinal sectional view of another embodiment of the screw decanter-type counter current centrifugal concentrator according to the present invention.

FIG. 6 is a partial cross-sectional view of still another embodiment of the screw decanter-type counter current centrifugal concentrator according to the present invention.

FIG. 7 is a partial longitudinal sectional view of the screw decanter-type counter current centrifugal concentrator of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Inner cylinder 3 Screw blade 4 Liquid flow path 5 Processing space 6 Concentrated liquid discharge port 7 Separate liquid discharge port 8 Feed disk 9 Guide vane 10 Flow path

Claims (8)

[Claims] 1. A screw decanter-type centrifugal concentrator characterized in that a liquid to be processed is fed into a processing space near an inner surface of an outer cylinder. 2. A centrifugal concentrator for supplying a liquid to be processed through a rotating shaft of an inner and outer cylinder, wherein a liquid supply passage for the liquid to be processed is extended to near an inner surface of the outer cylinder. 3. The screw decanter-type centrifugal concentrator according to claim 2, wherein the extended supply passage is a pipe extending to near the inner surface of the outer cylinder communicating with the flow path of the rotating shaft. 4. The screw decanter-type centrifugal concentrator according to claim 2, wherein the extended supply passage is formed by a feed disk extending from the inner cylinder surface to the vicinity of the outer cylinder inner surface. 5. The screw decanter-type concurrent centrifugal concentrator according to claim 4, wherein said extended supply passage is formed by a feed disk disposed at one end of the inner cylinder. 6. The extended supply passage is provided at a middle portion of the inner cylinder, and is formed by a feed disk disposed before and after a liquid supply hole provided in the inner cylinder. The screw decanter-type counter current centrifugal concentrator according to claim 4. 7. The screw decanter type according to claim 5, wherein said extended supply passage is formed by a feed disk and a substantially radially extending guide vane provided in said feed disk. Centrifugal concentrator 8. The feed disk according to claim 6, wherein a flow path of the liquid to be treated is provided in the vicinity of the surface of the inner cylinder, penetrating the feed disk, and extending in the direction of the rotation axis of the inner cylinder. 7 screw decanter type counter current centrifugal concentrator