JP4939590B2 - Vertical decanter centrifuge - Google Patents

Description

  The present invention relates to a vertical decanter centrifuge.

Conventionally, for example, when collecting pigment powder from a pigment fine powder liquid, when collecting a chlorinated polymer from a chlorinated polymer liquid, or when recovering a titanium oxide from a titanium oxide liquid, a solid-liquid separation is easy. Vertical decanter centrifuges using force are used.
FIG. 3 is a longitudinal sectional view showing a conventional vertical decanter centrifuge 20, and FIG. 4 is a right side view thereof. As shown in FIG. 3, the vertical decanter centrifuge 20 includes a rotating bowl 11 including a tapered portion 11 a and a cylindrical portion 11 b connected to the large-diameter end side of the tapered portion 11 a. It is provided coaxially and inserted through a screw conveyor 12 that rotates at a slight differential speed with respect to the rotating bowl 11, and an intubation hole 11d that protrudes into the center of the upper end plate 11c of the cylindrical portion 11b of the rotating bowl 11, Is connected to the lower part of the raw solution slurry supply pipe 15, and the raw solution slurry supplied into the rotary bowl 11 is supplied to the inner wall of the rotary bowl 11. The distribution rib plate 16b of the distribution member 16 that is uniformly distributed, the main motor 17 that rotates the rotating bowl 11 at a high speed, the number of rotations of the main motor 17 and A differential speed motor 19 and differential speed device 18 for rotating the screw conveyor 12 and to have a fast to a rotary bowl 11 in the same direction, the main portion is composed of (e.g., see Patent Document 1).
The differential speed device 18 conveys the solid separated by the specific gravity difference downward by the rotation of the screw conveyor 12 (phase difference due to the differential speed) and discharges it to the outside.
As shown in FIG. 4, the gantry 1 is a base for arranging or fixing the main components and pipes. This gantry 1 has a structure in which the vibration of the main body of the vertical decanter centrifuge 20 is not easily transmitted to the floor (foundation) of the factory.

Japanese Patent Laying-Open No. 2005-144279 (paragraph 0011, FIGS. 1 to 4 etc.)

  However, in the conventional vertical decanter centrifuge 20, when separating the stock solution slurry containing hard metal particles and the like, the hard metal particles collide with the screw blades 12 b, so that the outer edge portion of the screw blades 12 b wears early. . The wear of the screw blade portion 12b causes performance degradation and abnormal vibration. For this reason, as a countermeasure against wear, generally, a metal having high hardness, for example, tungsten carbide or ceramics, is welded or sprayed to take measures against wear. However, the conventional vertical decanter centrifuge 20 for processing a stock slurry containing fine metal powder having extremely high hardness, for example, alumina, silicon carbide, etc. cannot be dealt with only by increasing the hardness of the screw blade 12b. there were.

FIG. 5 is an enlarged cross-sectional view of the flow dividing member 16 of the conventional vertical decanter centrifuge 20 and the screw conveyor 12. FIG. 5A shows a stopped state, and FIG. 5B shows the flow of raw slurry in an operating state. Sectional drawing which shows, (c) is an enlarged view which shows the outer edge part of the screw blade | wing 12b.
As shown in FIG. 5 (a), the conventional vertical decanter centrifuge 20 is provided with a space hole 16h between the diverter member 16 directly below the stock slurry supply pipe 15, and the hole 16h. 6 are arranged in a radial pattern with six diverting rib plates 16b for equally distributing and diluting the stock solution slurry. The thickness of the diverting rib plate 16b is, for example, 20 to 30 mm.
A small and high protrusion 16a is formed at the center of the lower surface of the hole 16h. Further, the upper surface of the screw blade 12b formed in a spiral shape around the screw shaft 12a has a smooth flat shape.

  As shown in FIG. 5 (b), when the stock solution slurry containing hard metal particles flows from the stock solution slurry supply pipe 15 to the diverting member 16 directly below, the stock solution slurry is formed into a small and high protrusion 16 a formed at the center of the diverting member 16. Along the slanted surface, the flow falls to the outer peripheral direction, and the flow is converted from the vertical direction to the horizontal direction at a right angle. Then, the flow is divided by the six diverting rib plates 16 arranged radially, flows into the screw blades 12b arranged around the diverting member 16, and the solid matter having mass is moved downward by the action of centrifugal force, except for the solid matter. The separated liquid flows upward and is recovered. At this time, the hard metal particles of the stock solution slurry that has flowed into the upper surface of the screw blade 12b flow so as to collide with the screw blade 12b.

  As shown in FIG. 5C, in the conventional vertical decanter centrifuge 20 in which the stock slurry continuously flows into the screw blade 12b, the outer edge portion of the screw blade 12b is worn early. There was a problem that hard metal particles entered into the worn gap, and the groove portion 12c was formed by further expanding the wear, although locally.

  Accordingly, an object of the present invention is to provide a vertical decanter centrifuge that reduces the wear of screw blades even in a stock solution slurry containing hard metal particles.

Has been the invention of Vertical decanter centrifuge is defined in claim 1, a cylindrical rotating bowl erected, and screw conveyors provided coaxially within the rotary bowl, the stock solution into the rotating bowl A raw solution slurry supply pipe for supplying the slurry, and a plurality of flow-dividing rib plates provided at the lower end of the raw solution slurry supply pipe and radially provided to distribute the raw solution slurry to the inner wall of the rotating bowl, changed in the radial direction the flow of the slurry from the axial direction, Oite the Vertical decanter type centrifugal separator having a, a dividing member for supplying stock slurry on the inner wall side of the rotating bowl, the flow of the stock slurry once the center collected, radially concave formed in the dividing member diverting lifted upward Mito Kubo, on the upper surface of the screw blade roots formed in the screw conveyors, screw helical A guide portion having an axis center side is lower inclined surface of, and a stepped portion formed in the outer edge portion of the guide portion, the ratio of the width of said guide portion of the screw blade 10: 7-10: 9, a space is formed on the upper surface of the screw blade by the step portion between the step portion and the outer edge portion of the screw blade .
In the present invention, the guide portion is provided on the upper surface of a conventional screw blade so that a triangular convex portion can be separated or integrated in a sectional view, and the triangular hypotenuse portion becomes an inclined surface. The one formed as follows.

  According to the first aspect of the present invention, the screw blade of the screw conveyor is provided with a guide portion having an inclined surface inclined toward the axial center on the upper surface, thereby changing the flow path of the raw slurry and changing the flow. By dispersing, it is possible to provide a vertical decanter centrifuge that reduces the groove-like wear that has occurred locally.

Further, the invention according to claim 1, the lower surface of the dividing member to distribute the stock slurry by concave recesses were formed, changing the trajectory of the stock slurry stream by concave depressions, to distribute the flow Then, the flow of the stock solution slurry is then lifted and scattered above the guide portion having a spiral inclined surface inclined to the axial center side, and the flow path of the stock solution slurry is changed. The groove-shaped wear which has been generated locally can be reduced by separating the flow of the nozzle from the outer edge portion of the screw blade of the wear portion.

It is a longitudinal cross-sectional view of a vertical decanter centrifuge according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is an expanded sectional view of the screw conveyor of the vertical decanter type centrifuge which concerns on this invention, (a) is sectional drawing which shows a stop state, (b) is the a section enlarged view shown in (a), (c) is Sectional drawing which shows the flow of the undiluted | stock solution slurry of an operation state, (d) is an enlarged view which shows the outer edge part of a screw blade | wing. It is a longitudinal cross-sectional view of a conventional vertical decanter centrifuge. It is a side view of the conventional vertical decanter centrifuge. It is an expanded sectional view of the screw conveyor of the conventional vertical decanter type centrifuge, (a) shows a stopped state, (b) is a sectional view showing the flow of the undiluted slurry in the operating state, (c) is a screw blade It is an enlarged view which shows the outer edge part.

  An embodiment of a vertical decanter centrifuge according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, as described above, the vertical decanter centrifuge 10 according to this embodiment includes a tapered portion 11a formed at the lower portion and a cylindrical portion connected to the large-diameter end side of the tapered portion 11a. A rotating bowl 11 composed of a rotating bowl 11, a screw conveyor 2 that is provided coaxially with the rotating bowl 11 and rotates with a slight differential speed with respect to the rotating bowl 11, and a cylindrical portion 11 b of the rotating bowl 11. Provided in the central portion of the upper end plate 11 c and provided in connection with a raw solution slurry supply pipe 15 for supplying the raw solution slurry to a predetermined position in the rotating bowl 11 and a lower portion of the raw solution slurry supply pipe 15. A diverting rib plate 6b of the diverting member 6 that uniformly distributes the stock solution slurry supplied to the inner wall of the rotating bowl 11, and a main motor 17 that rotates the rotating bowl 11 at a high speed. Main unit from the rotational speed and some to have a differential speed 19 and differential speed electric motor for rotating the screw conveyor 2 and the rotary bowl 11 in the same direction to constitute the speed differential operation device 18. of the main motor 17 is configured.

  The rotating bowl 11 is formed by integrating a tapered portion 11a formed at the lower portion and a cylindrical portion 11b connected to the upper portion of the tapered portion 11a. A solid material discharge port 13 is provided at the lower end opening of the taper portion 11a. The solid matter of the fluid settles down to the inner wall side of the cylindrical portion 11b by the action of the centrifugal effect, moves downward by the screw blades 2b of the screw conveyor 2, and is discharged from the solid matter discharge port 13 to the outside.

  The stock solution slurry supply pipe 15 is a cylindrical pipe having a flange formed on the top thereof. In addition, as a method for supplying the raw solution slurry, it is desirable to supply the raw solution slurry into the rotary bowl 11 by a pump (not shown) through the raw solution slurry supply tube 15, but the raw solution slurry is passed from the head tank through the raw solution slurry supply tube 15 using gravity. You may supply in the rotating bowl 11. FIG.

In addition, the description which overlaps with description of the conventional vertical decanter-type centrifuge 20 shown in FIG. 3 mentioned above is abbreviate | omitted, and demonstrates in detail focusing on the difference.
In comparison between FIG. 3 and FIG. 1, the cross-sectional shape of the screw blade 12 b of the conventional screw conveyor 12 of FIG. 3 and the screw blade 2 b of the screw conveyor 2 of the present embodiment of FIG. 1 are greatly different. Moreover, the cross-sectional shape of the lower surface of the flow dividing member 16 and the lower surface of the flow dividing member 6 differs between the prior art and this embodiment.

The hole 6 h is a space formed at the center of the flow dividing member 6 located at the lower end of the stock solution slurry supply pipe 15.
The diverting rib plates 6b, 6b,... Are, for example, six plates that are provided radially around the hole 6h, and are rib-shaped plates that evenly distribute the stock solution slurry.
The flow dividing member 6 is connected to the lower end portion of the raw liquid slurry supply pipe 15 so as to guide the flow from the raw liquid slurry supply pipe 15 disposed in the hollow cylindrical screw conveyor 2.
Further, the upper end plate 11c shown in FIG. 1 is provided with, for example, 6 to 8 holes for the separation liquid overflow port 11e. A weir plate 7 is closed in a crescent shape at the separation liquid overflow port 11e of the hole and fixed by a bolt. As a result, the stock solution is blocked by the centrifugal force and the dam plate 7, and a liquid level 8 is formed along the inner wall surface of the rotating bowl 11 as shown in FIG.
By providing the flow dividing rib plates 6b, 6b in this way, the flow of the raw slurry can be changed from the axial direction to the radial direction, and the raw slurry can be reliably supplied to the inner wall side of the rotating bowl 11, so that the rotating bowl 11 A liquid surface 8 is formed by the weir plate 7 therein, and a residence time necessary for separating the solid matter in the raw slurry can be secured.

  Moreover, as shown to (a) of FIG. 2, the shape of the lower surface of the said flow dividing member 6 has provided the hollow 6a in the center in the substantially ball shape. The flow of the stock solution slurry is once collected in the center by the recess 6a, and is radially lifted upward from the concave recess 6a to be separated. The flow path is changed by the guide portion 2c provided with the inclined surface, and the flow is dispersed by colliding with the inner wall surface of the rotating bowl 11 away from the outer edge portion of the screw blade 2b. That is, as shown in FIG. 1, this flow collides with the stock solution in which the stock solution is retained by centrifugal force and the weir plate 7 by the centrifugal force and the flow is dispersed.

The screw conveyor 2 is a cylindrical screw shaft 2a, a screw blade 2b spirally wound around the screw shaft 2a, and integrally provided by welding, for example, and an upper surface of the screw blade 2b. It is formed from the guide part 2c which has the inclined surface inclined in the direction.
In addition, the guide part 2c in which the said inclined surface was formed should just be provided in the range of the predetermined area | region which covers the discharge outlet branched radially of a raw | natural liquid slurry, and can reduce the said local wear.

  As shown in FIG. 2B, the inclination angle θ of the inclined surface of the guide portion 2c of the screw blade 2b is preferably 10 degrees, for example, but may be in the range of 5 to 15 degrees. Furthermore, the ratio of the width b of the screw blade 2b and the width c of the guide portion 2c is preferably 10: 7, but may be 10: 8, 10: 9, or any other ratio. A triangular projection shape is formed at this ratio, and a step 2d is formed in the vicinity of the outer edge. The thickness t of the outer edge portion of the screw blade 2b is the same as the thickness of the conventional screw blade 12b, but the inclined surface of the inclination angle θ is set so that the thickness of the stepped portion 2d is about twice as thick. Provided.

<Flow of stock slurry containing hard metal powder>
As shown in FIG. 1, when the main motor 17 is driven, the high speed shaft 3 rotates via the belt 11h and the pulley 11f. When the high-speed shaft 3 rotates, the rotating bowl 11 rotates at high speed. When the differential speed motor 19 is driven, the low speed shaft 4 is rotated via the belt 12h and the pulley 12f, and the screw conveyor shaft 2 is rotated at a low speed in the same direction.
Therefore, when the stock solution slurry is supplied from the stock solution slurry supply pipe 15, as shown in FIG. 2C, the flow of the stock solution slurry is temporarily caused by the center recess 6a of the flow dividing member 6 to the bottom of the center recess 6a. Then, the flow of the stock slurry is lifted upward from the concave depression 6a and is evenly divided radially. The diverted flow is discharged from a radial discharge port, and further guided to an inclined surface guide portion 2c inclined on the axial center side on the upper surface of the screw conveyor 2, and is divided upward. As a result, the outer edge of the screw blade 2b The stock slurry is separated from the part and is made to collide upward toward the stock solution on the liquid surface 8 staying on the inner wall surface of the rotating bowl 11 to disperse the flow.

FIG. 2D is an enlarged view showing an outer edge portion of the screw blade 2b. The present invention has succeeded in changing the flow path of the raw slurry concentrated on the outer edge of the conventional screw blade 12b and dispersing it away from the outer edge of the screw blade 2b.
As a result of the test by long-time operation, there is no occurrence of groove-like wear that has been locally generated until now. That is, it has been found that it is effective in slowing and reducing the progress of wear. As a result, the present invention is a vertical decanter that reduces local groove-like wear at the outer edge of the screw blade, which cannot be solved by simply welding or spraying a hard metal to the screw blade as in the conventional anti-wear measures. A centrifugal separator can be provided.

Next, the operation of the vertical decanter centrifuge 10 having the above configuration will be described.
When the start button of the electric motor 17 is pressed, the rotating bowl 11 rotates at a high speed (for example, 2000 to 4000 min ⁻¹ ). When the start button of the differential speed motor 19 is pressed, the rotational speed of the differential speed motor 19 is determined with respect to the rotational speed of the main motor 17, and the screw conveyor 2 is rotated at a lower speed than the rotational speed of the main motor 17. Rotates.
The stock solution slurry is supplied to a predetermined position inside the rotating bowl 11 through the stock solution slurry supply pipe 15 and the flow dividing member 6. Solids in the raw slurry supplied from the flow dividing member 6 to the cylindrical portion 11b of the rotating bowl 11 are subjected to centrifugal force and settle to the inner wall side of the cylindrical portion 11b. The settled solid matter is drained by the action of gravity until it is lifted up by the screw blade 12b of the screw conveyor 12 toward the tapered portion 11a and conveyed to the solid matter discharge port 13. Then, the drained solid matter is discharged to the outside from the solid matter discharge port 13 as a solid matter.
On the other hand, the separated liquid separated in the rotating bowl 11 passes through the separated liquid overflow port 11e provided in the upper end plate 11c of the cylindrical portion 11b, overflows the weir plate 7 and is separated from the separated liquid discharge port 14. Discharged to the outside.

As mentioned above, although embodiment of this invention was described, it can change suitably and can implement without being limited to this embodiment. Here, the guide part 2c is attached to the screw blade 2b and described as a removable segment system. However, the screw blade 2b and the guide part 2c may be integrally formed.
Further, another part in which the concave depression 6 a is formed may be manufactured and attached to the lower surface of the flow dividing member 6.
Furthermore, it may be carried out together with the conventional wear countermeasures. When implemented in conjunction with conventional wear countermeasures, a dramatic increase in service life can be expected.

DESCRIPTION OF SYMBOLS 1 Stand 2 Screw conveyor 2a Screw shaft 2b Screw blade 2c Guide part 2d Step part 3 High speed shaft 4 Low speed shaft 6 Flow dividing member 6a Depression 6b Flow dividing rib plate 6h Hall 7 Dam plate 8 Liquid level 10 Vertical decanter centrifuge

Claims (1)

A cylindrical rotating bowl erected,
And screw conveyors provided coaxially within the rotary bowl,
A stock slurry supply pipe for feeding stock solution slurry into the rotating bowl;
A plurality of diverting rib plates are provided at the lower end of the stock solution slurry supply pipe and radially provided to distribute the stock solution slurry to the inner wall of the rotating bowl, and the flow of the stock solution slurry is changed from the axial direction to the radial direction. Changing, a flow dividing member for supplying the raw solution slurry to the inner wall side of the rotating bowl ,
Oite the Vertical decanter type centrifugal separator having a
The stock solution flow of the slurry once collected in the center, radially concave formed in the dividing member diverting lifted upward Mito Kubo,
The upper surface of the screw blade roots formed in the screw conveyors, a guide portion having an axis center side is lower inclined surface of the screw shaft in a spiral shape,
A stepped portion formed at the outer edge of the guide portion ;
With
The ratio between the width of the screw blade and the width of the guide portion is 10: 7 to 10: 9, and a space is formed on the upper surface of the screw blade by the step portion between the step portion and the outer edge portion of the screw blade. Vertical decanter type centrifugal separator, characterized in that but formed.

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