Centrifugal concentrator

Abstract

To solve a problem of a conventional centrifugal thickener that undiluted liquid is easy to be mixed in a separate liquid and classification performance is not sufficient.SOLUTION: A centrifugal thickener of the present invention includes: a cylindrical rotary bowl; a screw conveyor provided in the rotary bowl, configured to move concentrated liquid settled in an inner circumferential surface of the rotary bowl from one position to the other position, and including a screw blade provided such that a tip end portion thereof is in proximity to an inner circumferential surface of the rotary bowl; rotary means that rotates the rotary bowl and the screw conveyor; an undiluted liquid supply part that supplies undiluted liquid containing fine particles, from one side of the rotary bowl, from the outside to the inside of the rotary bowl; a concentrated liquid discharge part that discharges concentrated liquid separated by centrifugal force due to rotation of the rotary bowl, from the other side of the rotary bowl; and a separate liquid discharge part that discharges, to the outside of the rotary bowl, cleared separate liquid obtained by being separated by the centrifugal force due to rotation of the rotary bowl. The undiluted liquid supply part includes undiluted liquid input means that inputs the undiluted liquid to a position in proximity to the inner circumferential surface of the rotary bowl.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a centrifugal concentrator, specifically a screw decanter type centrifugal concentrator that can be used as a concentrator (including a classifier and a separator) for performing solid-liquid separation of raw liquid containing fine particles.

[0002] The present invention also relates to a centrifugal concentrator that is a closed type using a skimming method that utilizes the pushing effect of internal pressure to discharge low-viscosity concentrated liquid, and is capable of continuous concentration (including classification and separation). [Background technology]

[0003] A skimming-type screw decanter centrifugal concentrator is configured with a cylindrical rotating bowl that rotates at high speed around its axis, and a screw conveyor incorporated into the rotating bowl that rotates at differential speeds to move the sediment (concentrated liquid) that has accumulated (settled) on the inner surface (inner wall surface) of the rotating bowl from one side to the other in the axial direction.

[0004] Of the raw liquid supplied from one side of the raw material supply unit into the rotating bowl, solids (fine particles) with a high specific gravity separate, settle and concentrate on the inner wall of the rotating bowl, while the liquid is clarified and separated. The settled concentrated liquid is then sent by the screw conveyor to the other side of the rotating bowl and discharged from a concentrated liquid discharge unit formed on the other side, and the clarified separated liquid is discharged from the separated liquid discharge unit.

[0005] (1.1. Description of conventional centrifugal concentrators (conventional machines))

[0006] An example of the configuration of a conventional centrifugal concentrator will be described below.

[0007] FIG. 17 shows a conventional skimming type screw decanter centrifugal concentrator.

[0008] Reference numeral 1 denotes a cylindrical rotating bowl. The rotating bowl 1 comprises a cylindrical main body 1a having a circular inner cross section, one and the other side walls 1b, 1c, and support shafts 2, 3 that protrude outward from the axial centers of the side walls 1b, 1c and have through holes 2a, 3a that extend in the axial direction and communicate with the interior of the rotating bowl 1.

[0009] The support shafts 2 and 3 are rotatably supported by bearings 7a and 7b, respectively, and are configured to rotate at high speed by a rotating means (not shown), such as a motor, connected to a pulley 2b fixed to the support shaft 2.

[0010] Furthermore, reference numeral 4 denotes a screw conveyor disposed coaxially within the rotating bowl 1. The screw conveyor 4 comprises a cylindrical body 4a disposed within the rotating bowl 1, a spiral screw blade 4b disposed on the outer circumferential surface of the body 4a from one end to the other, one rotating shaft 5 disposed so as to protrude outward from the axial center of one side of the body 4a, and the other rotating shaft 6 disposed so as to protrude outward from the axial center of the other side of the body 4a, and the tip portion of the screw blade 4b is formed so as to be close to the inner circumferential surface of the rotating bowl 1.

[0011] Furthermore, one rotating shaft 5 and the other rotating shaft 6 of the body portion 4a extend outward through the through holes 2a and 3a of the one and other support shafts 2 and 3, respectively, and are rotatably supported by bearings 7c and 7d. For example, they are configured to rotate by a rotating means (not shown), such as a motor, connected to a pulley 5a fixed to the rotating shaft 5, thereby rotating the body portion 4a.

[0012] In addition, the raw liquid supply pressure is used to discharge the concentrated liquid from the skimming tube described later, and in order to maintain this pressure within the machine (inside the rotating bowl), a seal such as an oil seal 15 is provided between the rotating bowl 1 and the screw conveyor 4.

[0013] The centrifugal concentrator is also provided with a raw liquid supply unit, for example, at one end side, for supplying raw liquid from the outside into the rotary bowl 1.

[0014] The concentrate supply section comprises, for example, a concentrate supply hole 8 extending axially from one end of one of the rotating shafts 5 to one end of the body portion 4a, and one or more concentrate discharge holes 9 which communicate with the other end of the concentrate supply hole 8, extend radially to the outer circumferential surface of the body portion 4a, and communicate with the inside of the rotary bowl 1.

[0015] One end of the raw liquid supply hole 8 is connected via a rotary joint (not shown) or the like to a raw liquid supply means that supplies raw liquid at a desired pressure, for example, a raw liquid supply pipe (not shown) that is connected to a raw liquid metering pump (not shown), and the raw liquid supplied from the raw liquid supply pipe is discharged from the outer peripheral surface of the body portion 4a into the rotary bowl 1 through the raw liquid supply hole 8 and the raw liquid discharge hole 9.

[0016] In addition, the centrifugal concentrator is provided, for example, at the other end thereof, with a separated liquid discharge section for discharging the clarified separated liquid in the rotating bowl 1 to the outside, and a concentrated liquid discharge section for discharging the concentrated liquid to the outside.

[0017] The separated liquid discharge section is composed of, for example, a separated liquid discharge hole 10 extending in the axial direction from the other end of the other rotating shaft 6 to the other end of the body portion 4a, and one or more separated liquid introduction holes 11 that communicate with one end of the separated liquid discharge hole 10 and extend in the radial direction to the outer circumferential surface of the body portion 4a.

[0018] The separated liquid in the rotating bowl 1 is introduced into the separated liquid inlet hole 11 from the outer peripheral surface of the body portion 4a, and then passes through the separated liquid outlet hole 10 and is discharged to the outside of the rotating bowl 1 from the other end opening 10a of the hole 10.

[0019] The concentrated liquid discharge section comprises, for example, a concentrated liquid discharge pipe 12 provided coaxially within the separated liquid discharge hole 10, and a skimming section that introduces the concentrated liquid that has settled on the inner peripheral surface of the rotating bowl 1 into the concentrated liquid discharge pipe 12. The skimming section comprises, for example, a skimming tube 13 that communicates with one end of the concentrated liquid discharge pipe 12. The skimming tube 13 extends in the radial direction, penetrates the rotating shaft 6, and has a tip opening that is close to the inner peripheral surface of the rotating bowl 1.

[0020] The concentrated liquid that has settled on the inner surface of the rotating bowl 1 is introduced into the skimming tube 13, passes through the concentrated liquid discharge tube 12, and is discharged outside the rotating bowl 1 from the other end opening 12a of the tube 12.

[0021] A concentrated liquid concentration adjusting device 14 is provided at the other end opening 12a of the concentrated liquid discharge pipe 12, and this device 14, for example, continuously measures the viscosity of the discharged concentrated liquid and electrically moves a valve back and forth to change the opening amount of the other end opening and adjust the concentration of the concentrated liquid.

[0022] The separated liquid discharge portion may be provided on one side of the body portion 4a instead of on the other side thereof.

[0023] (1.2. Explanation of the operation of conventional centrifugal concentrators)

[0024] Next, a method of using the conventional centrifugal concentrator will be described.

[0025] First, the rotary bowl 1 is rotated at a high speed, and the screw conveyor 4 is rotated at a desired speed difference relative to the rotary bowl 1.

[0026] Then, the concentrate from the concentrate supply means is supplied through the concentrate supply unit into the rotating bowl 1. That is, by a metering pump or by quantitative control, the concentrate is supplied from the concentrate supply pipe to the concentrate supply hole 8, and is supplied from the outer peripheral surface of the body portion 4a into the rotating bowl 1 through the concentrate discharge hole 9.

[0027] The raw liquid supplied into the rotating bowl 1 is separated by the centrifugal force of the rotating bowl 1 into a concentrated liquid with a high solid content and a clarified separated liquid.

[0028] The concentrated liquid is then moved by the screw blade 4b along the inner surface of the rotating bowl 1 to the other side, and is introduced into the skimming pipe 13 using the internal pressure, and is then discharged out of the rotating bowl 1 through the concentrated liquid discharge pipe 12.

[0029] The concentration of the discharged concentrated liquid is adjusted by the concentrated liquid concentration adjusting device 14.

[0030] The separated liquid is discharged from the outer peripheral surface of the body portion 4a to the outside of the rotary bowl 1 through the separated liquid inlet hole 11 and the separated liquid outlet hole 10.

[0031] For example, Patent Document 1 discloses a skimming-type screw decanter centrifugal concentrator. [Prior art documents] [Patent documents]

[0032] [Patent Document 1] Figure 1 of the Unexamined Japanese Utility Model Application Publication No. 62-79556 Summary of the Invention [Problem to be solved by the invention]

[0033] However, in the conventional centrifugal concentrator, the raw liquid supply position and the separated liquid discharge position are at the same level (equally distant from the axis) on the surface of the screw conveyor body, which makes it easy for raw liquid particles to get caught in the separated liquid.Furthermore, this position has the lowest centrifugal effect and a small separation circumferential area, resulting in a decrease in separation performance.

[0034] That is, in the settling zone, the raw liquid is introduced from the surface of the screw conveyor body where the centrifugal force is lowest, and the settling distance to the inner circumferential surface of the rotating bowl is long. In addition, the separated liquid outlet is located on the same surface of the screw conveyor body as the raw liquid inlet, so that the raw liquid is likely to be entrained, leading to a decrease in the efficiency of solid-liquid separation.

[0035] Furthermore, in order to maintain the pressure inside the machine (inside the rotating bowl), a seal such as an oil seal is provided between the rotating bowl 1 and the screw conveyor 4, but this oil seal needs to be replaced periodically and may cause unexpected trouble.

[0036] The present invention employs a skimming method similar to that of the conventional method, but is expected to improve separation performance by supplying the raw liquid from a level position at the tip of the screw blade close to the inner circumferential surface of the rotating bowl, which has the shortest sedimentation distance, the greatest centrifugal effect, and the largest circumferential separation area.

[0037] Another object is to eliminate the need for a seal and reduce trouble. [Means for solving the problem]

[0038] In order to achieve the above object, the centrifugal concentrator of the present invention comprises a rotatable cylindrical rotating bowl, a screw conveyor provided within the rotating bowl and having screw blades with their tips provided close to the inner peripheral surface of the rotating bowl for moving concentrated liquid that has settled on the inner peripheral surface of the rotating bowl from one side to the other in the axial direction, a rotating means for rotating the rotating bowl and the screw conveyor, a raw liquid supply unit provided on one side of the rotating bowl for supplying raw liquid containing fine particles from the outside to the inside of the rotating bowl, and a rotating means provided on the other side of the rotating bowl for supplying raw liquid containing fine particles from the outside to the inside of the rotating bowl. The screw conveyor comprises a concentrated liquid discharge section that discharges the concentrated liquid moved by the conveyor from the inside of the rotating bowl to the outside, and a separated liquid discharge section that discharges the clarified separated liquid from the inside of the rotating bowl by the centrifugal force caused by the rotation of the rotating bowl to the outside, the raw liquid supply section has a raw liquid input means that inputs the raw liquid to a position close to the inner peripheral surface of the rotating bowl, the raw liquid input means being a raw liquid diffusion disk that is provided on the outer peripheral surface of one end side of the body part of the screw conveyor and has an outer peripheral surface that is close to the inner peripheral surface of the rotating bowl, the raw liquid is input by the raw liquid diffusion disk to a position close to the inner peripheral surface of the rotating bowl through a gap between the outer peripheral surface of the raw liquid diffusion disk and the inner peripheral surface of the rotating bowl, and the outer peripheral surface of the raw liquid diffusion disk or at a plurality of locations spaced at a desired distance in the circumferential direction. The rotating bowl is characterized by being provided with a stirring blade to prevent the supplied stock solution from adhering to the inner peripheral surface of the rotating bowl.

[0040] The concentrated liquid discharge section is characterized in that it comprises a concentrated liquid discharge hole formed in the rotating shaft on the other end side of the screw conveyor, and a skimming section that communicates with one end of the concentrated liquid discharge hole, extends to a position close to the inner circumferential surface of the rotating bowl, and introduces the concentrated liquid that has settled on the inner circumferential surface into the concentrated liquid discharge hole.

[0041] In addition, the cantilever type of the present invention No oil seal is usedThe centrifugal concentrator comprises a cylindrical rotating bowl that is rotatably provided, a screw conveyor provided in the rotating bowl and having screw blades whose tip ends are provided close to the inner peripheral surface of the rotating bowl, which moves the concentrated liquid that has settled on the inner peripheral surface of the rotating bowl from one side to the other in the axial direction, a rotating means for rotating the rotating bowl and the screw conveyor, a raw liquid supply unit provided on one side of the rotating bowl that supplies raw liquid containing fine particles from the outside to the inside of the rotating bowl, and a centrifugal separator provided on the other side of the rotating bowl. a concentrated liquid discharge section that discharges, from inside the rotating bowl, the concentrated liquid that has settled on the inner peripheral surface of the rotating bowl due to centrifugal force and been moved by the screw conveyor, and a separated liquid discharge section that discharges, from inside the rotating bowl, the separated liquid that has been clarified by the centrifugal force caused by the rotation of the rotating bowl; the rotating bowl comprises a cylindrical main body, one and other side walls that close one and other openings of the cylindrical main body, a support shaft that is provided on one side wall so as to protrude outward, and a through-hole that is formed in the other side wall; and the rotation shaft of the screw conveyor is provided on the cylindrical main body so as to protrude outward, the raw liquid supply unit is formed only on the other end side of the body portion, and the rotating shaft penetrates a through-hole formed in the other side wall of the rotating bowl, protruding outward, and is supported in a cantilevered manner so as to be rotatable; the raw liquid supply unit has a through-hole extending in the axial direction from one end of the support shaft connected to raw liquid supply means for supplying raw liquid at a desired pressure, penetrating one side wall of the rotating bowl, and communicating with the inside of the rotating bowl; and raw liquid introduction means formed to introduce raw liquid from the through-hole of the support shaft to a position close to the inner circumferential surface of the rotating bowl, the raw liquid introduction means being provided on the outer circumferential surface of one end side of the body portion of the screw conveyor, a concentrate dispersing disc having an outer peripheral surface close to the inner peripheral surface of the rotating bowl, and the concentrate dispersing disc allows the concentrate to be introduced into the rotating bowl at a position close to the inner peripheral surface through a gap between the outer peripheral surface of the concentrate dispersing disc and the inner peripheral surface of the rotating bowl; the concentrated liquid discharge section comprises a concentrated liquid discharge hole formed in the rotating shaft on the other end side of the screw conveyor, connected to a means for adjusting the amount of concentrated liquid discharged; and a skimming section for introducing the concentrated liquid that has settled on the inner peripheral surface of the rotating bowl into the concentrated liquid discharge hole, and the skimming section is provided on the outer peripheral surface of the other end side of the screw conveyor and has an outer peripheral surface:The apparatus comprises a disk formed in proximity to the inner peripheral surface of the rotating bowl, and a skimming hole formed in the disk, communicating with one end of the concentrated liquid discharge hole and opening radially to the outer peripheral surface, and the separated liquid discharge section comprises an opening between the rotating shaft and a through-hole formed in the other side wall of the rotating bowl, and a pressure adjusting means provided in the opening for adjusting the opening size of the opening to adjust the pressure inside the rotating bowl.

[0042] In addition, the outer peripheral surface of the liquid diffusion disc or at a plurality of locations spaced at a desired distance in the circumferential direction. The rotating bowl is characterized by being provided with a stirring blade to prevent the supplied stock solution from adhering to the inner peripheral surface of the rotating bowl. [Effects of the Invention]

[0043] According to the present invention, improved separation performance can be expected by supplying the raw liquid from a level position at the tip of the screw blade close to the inner circumferential surface of the rotating bowl, which has the shortest sedimentation distance, the greatest centrifugal effect, and the largest circumferential separation area.

[0044] Furthermore, sealing parts can be eliminated, reducing trouble. [Brief explanation of the drawings]

[0045] [Figure 1] 1 is a longitudinal sectional side view of a centrifugal concentrator (cantilever type) of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] 1 is an explanatory diagram of a concentrated liquid concentration adjusting device for a centrifugal concentrator according to the present invention. [Figure 4] FIG. 2 is an explanatory diagram of a centrate control valve of the centrifugal concentrator of the present invention. [Figure 5] 1 is a longitudinal sectional side view of a centrifugal concentrator (double-supported type) of the present invention. [Figure 6] FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5. [Figure 7] 1 is a schematic diagram of the sedimentation state of the centrifugal concentrator of the present invention. [Figure 8] FIG. 2 is a diagram showing the flow of liquid in the centrifugal concentrator of the present invention. [Figure 9] FIG. 1 is a diagram showing the relationship between the classified particle size determined from the balance between centrifugal force and drag force in the centrifugal concentrator of the present invention. [Figure 10] FIG. 2 is a diagram showing the sedimentation state in the centrifugal concentrator of the present invention. [Figure 11] FIG. 2 is a diagram showing the dimensions of the centrifugal concentrator of the present invention. [Figure 12] FIG. 1 is a diagram showing dimensions, symbols, and units in a simulation of a centrifugal concentrator according to the present invention and a conventional centrifugal concentrator. [Figure 13] FIG. 1 is a schematic diagram of the sedimentation state of a conventional centrifugal concentrator. [Figure 14] FIG. 1 is a diagram showing the flow of liquid in a conventional centrifugal concentrator. [Figure 15] FIG. 1 is a diagram showing the sedimentation state in a conventional centrifugal concentrator. [Figure 16] FIG. 1 is a diagram showing the dimensions of a conventional centrifugal concentrator. [Figure 17] FIG. 1 is a vertical cross-sectional side view of a conventional centrifugal concentrator. DETAILED DESCRIPTION OF THE INVENTION

[0046] Examples of modes for carrying out the present invention are shown below. [Example]

[0047] (2.1. Description of the centrifugal concentrator of the present invention) (cantilever structure type)

[0048] A first embodiment of the present invention will be described with reference to FIGS.

[0049] The centrifugal concentrator of Example 1 of the present invention has a screw conveyor with a cantilever structure and does not use a sealing part such as an oil seal, so that the structure is simple and it can be considered to be applicable to small machines.

[0050] As shown in Figures 1 and 2, the skimming-type screw decanter centrifugal concentrator of the present invention comprises a cylindrical rotating bowl 16 that rotates at high speed around its axis, a screw conveyor 17 that is coaxially arranged within this rotating bowl 16 and moves sediment (concentrated liquid) that has accumulated (settled) on the inner surface (inner wall surface) of the rotating bowl 16 from one side to the other in the axial direction, a raw liquid supply section, a concentrated liquid discharge section, and a separated liquid discharge section, and the raw liquid supply section supplies the raw liquid from a position close to the inner surface of the rotating bowl 16 (a level position near the tip of the screw conveyor blades).

[0051] That is, although the present invention has a basic structure similar to that of conventional centrifugal concentrators, as can be seen from the fact that the classified particle size in Table 1 described below becomes smaller the closer to the inner circumferential surface of the rotating bowl 16, the closer the stock solution is charged to the inner circumferential surface of the rotating bowl 16, the better the classification accuracy. Therefore, the stock solution charging position is set to a position close to the inner circumferential surface of the rotating bowl 16.

[0052] Note that supplying from a position close to the inner peripheral surface of the rotating bowl 16 means supplying from a higher position (on the inner peripheral surface of the rotating bowl) that is at least 80% of the radius from the center of the screw conveyor, assuming that the radius from the center of the screw conveyor to the tip of the screw blade is 100%. However, better classification accuracy can be achieved by supplying from a higher position that is at least 90% of the radius from the center of the screw conveyor, preferably at least 95% of the radius, and more preferably at least the tip of the blade (100%).

[0053] For example, in the screw conveyor, if the radius from the center of the screw conveyor to the tip of the screw blade is 0.17 m, the level position at 80% of the radius from the center of the screw conveyor indicates a position of 0.136 m, the level position at 90% of the radius indicates a position of 0.153 m, the level position at 95% of the radius indicates a position of 0.1615 m, and the level position at the tip of the blade means 0.17 m.

[0054] The stock solution may be supplied from the inner peripheral surface of the rotating bowl.

[0055] An example of the configuration of the present invention will now be described in detail.

[0056] The rotating bowl 16 is formed, for example, by a cylindrical main body 16a having a circular inner cross-sectional shape, one and the other side walls 16b, 16c that close one and the other openings of the cylindrical main body 16a, a support shaft 18 that protrudes outward from the axial center of one of the side walls 16b, and a through hole 19 formed in the axial center of the other side wall 16c.

[0057] The support shaft 18 is rotatably supported by bearings 20 and is configured to rotate at high speed by a rotating means (not shown), such as a motor, connected to a pulley 21 fixed to the support shaft 18.

[0058] The rotary bowl 16 may be supported at both ends by supporting the other end of the rotary bowl 16 in addition to being supported at one end by supporting only the support shaft 18.

[0059] The screw conveyor 17 also comprises a cylindrical body 17a provided within the rotating bowl 16, a spiral screw blade 17b provided on the outer circumferential surface of the body 17a from one end to the other with its tip close to the inner circumferential surface of the rotating bowl 16, and a rotating shaft 22 formed at the axial center of the other side surface of the body 17a and protruding outward.

[0060] The rotating shaft 22 of the body portion 17a passes through the through-hole 19 of the rotating bowl 16, extends outward, and is rotatably supported by bearings 23. For example, the rotating shaft 22 is configured to be rotated by a rotating means (not shown), such as a motor, connected to a pulley 24 fixed to the rotating shaft 22. The body portion 17a is supported in a cantilevered manner and rotates at a desired speed difference relative to the rotating bowl 16.

[0061] The raw material supply section includes, for example, a through hole 18a extending axially from one end of the support shaft 18 through one side wall of the rotating bowl 16 and communicating with the interior of the rotating bowl 16, and raw material introduction means formed to introduce the raw material from the through hole 18a into a position close to the inner circumferential surface of the rotating bowl 16 (near the level position of the tip portion of the screw blade 17b).

[0062] The raw material introduction means is, for example, a disk-shaped raw material diffusion disk 25 that is coaxially provided on the outer peripheral surface of one end side of the body portion 17a of the screw conveyor 17 and whose outer peripheral surface is close to the inner peripheral surface of the rotating bowl 16.

[0063] One end of the through hole 18a is connected via a shaft sealing means such as a rotary joint 28 to a stock solution supplying means for supplying the stock solution at a desired pressure, for example, a stock solution supply pipe 27 connected to a stock solution metering pump 26. The stock solution supplied from the stock solution supply pipe 27 passes through the through hole 18a, and is then moved by the stock solution diffusing disk 25 between the side wall of the rotating bowl 16 and the side surface of the stock solution diffusing disk 25, and is supplied from an input opening between the inner peripheral surface of the rotating bowl 16 and the stock solution diffusing disk 25 to a level position near the tip of the screw blade 17b.

[0064] In addition, stirring blades 29 may be provided at one location on the outer peripheral surface of the stock solution-diffusing disk 25 or at multiple locations spaced a desired distance apart in the circumferential direction to prevent the supplied stock solution from adhering to the inner peripheral surface of the rotating bowl 16.

[0065] Instead of using a concentrate diffusion disk as the concentrate introduction means, the concentrate from the through-hole 18a may be introduced into a position close to the inner circumferential surface of the rotating bowl 16 using a means such as a pipe, or instead of the other end of the through-hole 18a penetrating one side wall 16b of the rotating bowl 16, the other end may extend radially outward within the one side wall 16b and further extend to one end of the cylindrical main body 16a of the rotating bowl 16 so as to penetrate into the cylindrical bowl 16, allowing the concentrate to be introduced into the rotating bowl 16 from one end side of the inner circumferential surface of the cylindrical main body 16a.

[0066] Furthermore, as the raw liquid supply section, for example, a through hole may be provided on one end side of the outer peripheral wall of the cylindrical main body portion 16a of the rotating bowl, and the raw liquid may be introduced into the rotating bowl 16 through the through hole.

[0067] The concentrated liquid discharge section comprises, for example, a concentrated liquid discharge hole 30 extending axially from the other end of the rotating shaft 22 to the other end of the body portion 17a, and a skimming section that introduces the concentrated liquid that has settled on the inner surface of the rotating bowl 16 into the concentrated liquid discharge hole 30. The skimming section comprises, for example, a disk body 31 that is coaxially provided on the outer peripheral surface of the other end side of the body portion 17a and has an outer peripheral surface that is formed so as to be close to the inner peripheral surface of the rotating bowl 16, and one or more skimming holes 32 that are provided in the disk body 31 and communicate with one end of the concentrated liquid discharge hole 30 and open radially to the outer peripheral surface.

[0068] The concentrated liquid that has settled on the inner surface of the rotating bowl 16 is introduced into the skimming hole 32 from the outer surface of the disk body 31, and then discharged out of the rotating bowl 16 through the concentrated liquid discharge hole 30 by a concentrated liquid metering discharge pump 34 that adjusts the discharge amount of the concentrated liquid and is connected to the other end of the concentrated liquid discharge hole 30 via a rotary joint 33 (rotary joint, mechanical seal) or the like.

[0069] The concentrated liquid constant rate discharge pump 34 detects the viscosity of the concentrated liquid being discharged and adjusts the pump flow rate, thereby making it possible to control the concentration of the concentrated liquid.

[0070] Instead of using the rotary joint 33 and the pump 34, a concentrated liquid concentration adjusting device 35 may be provided at the other end opening of the concentrated liquid discharge hole 30 as shown in FIG. 3, which detects the viscosity of the concentrated liquid being discharged and electrically changes the opening size of the opening to control the concentration of the concentrated liquid.

[0071] 3, the concentrate concentration adjusting device 35 comprises a stepping motor unit 36, a main body 39 threadedly engaged with a threaded portion 38 formed on a rotary shaft 37 of the stepping motor 36 and movable back and forth but restricted in its axial rotation relative to the stepping motor unit 36, and a conical valve body 40 provided at the tip of the main body 39. When the rotary shaft 37 of the stepping motor unit 36 ​​rotates under the control of a control unit, the main body 39 moves back and forth, and the tip of the valve body 40 changes the opening of the other end opening of the concentrate discharge hole 30, thereby changing the amount of concentrate discharged and the concentration of the concentrate.

[0072] The separated liquid discharge section is composed of, for example, an opening between the rotary shaft 22 and a through-hole 19 formed in the other side wall 16c of the rotary bowl 16, and a pressure adjusting means inside the rotary bowl, such as a separated liquid control valve 41, which is provided at the opening and controls the opening size of the opening to maintain an internal pressure that allows the concentrated liquid to be discharged from the skimming section.

[0073] As shown in FIG. 4, the separated liquid control valve 41 includes a cone 42, a through-hole 43 formed at the axial center of the cone 42 and passing through the rotary shaft 22 to allow it to move freely in the front-to-rear direction, another end surface 42a of the cone 42, a flange 44 provided on the outer circumferential surface of the rotary shaft 22 at a desired distance, and a spring means such as a coil spring 45 inserted into the rotary shaft 22 between the other end surface 42a of the cone 42 and the flange 44.

[0074] The discharge pressure of the separated liquid causes the opening between the opening 19 and the rotating shaft 22 to be displaced in the front-to-rear direction, changing the opening size of the opening. Since the internal pressure of the machine is determined by the discharge amount of the separated liquid, a spring having a spring force that will achieve the desired internal pressure is provided.

[0075] The separated liquid near the surface of the body is discharged through the through-hole 47 and from the opening between the through-hole 19 and the rotating shaft 22, and the separated liquid control valve 41 maintains an internal pressure that allows the concentrated liquid to be discharged from the skimming section.

[0076] The separated liquid control valve 41 may also be configured to adjust the opening amount of the opening and control the internal pressure to a predetermined value by other methods, such as a device that detects the pressure inside the rotary bowl and electrically adjusts the valve opening.

[0077] In addition, a separated liquid discharge chamber 46 covering the through-hole 19 and the separated liquid control valve 41 may be provided on the outer surface of the other side wall 16c of the rotating bowl 16, and the separated liquid discharged from the through-hole 19 may be stored and discharged, for example, from a discharge port 46a formed in the bottom of the separated liquid discharge chamber 46.

[0078] Furthermore, the disk body 31 is provided with one or more axial through-holes 47 for passing the separated liquid at a level position on the outer circumferential surface of the body portion 17a, so that the separated liquid in the rotating bowl 16 can be smoothly discharged from the through-holes 19 to the outside of the rotating bowl 16 through the through-holes 47. The through-holes 47 are provided at positions that do not interfere with the skimming holes 32.

[0079] In addition, stirring blades 48 may be provided at one location near the skimming section opening on the outer surface of the disk body 31, or at multiple locations spaced a desired distance apart in the circumferential direction, to fluidize the concentrated liquid and allow it to be discharged smoothly.

[0080] (2.2. Description of the Function of the Present Invention)

[0081] Next, a method for using the centrifugal concentrator of the present invention will be described.

[0082] In the centrifugal concentrator of the present invention, the rotary bowl 16 is rotated at a high speed, and the screw conveyor 17 is rotated at a desired speed difference relative to the rotary bowl 16.

[0083] The stock solution is pressurized and supplied by a constant-volume supply pump 26 or constant-volume control, passes through a stock solution supply pipe 27, a rotary joint (rotary joint, mechanical seal, etc.) 28 of the shaft sealing means, and through-hole 18a formed in the support shaft 18, and then moves between the side wall of the rotary bowl 16 and the side surface of the stock solution diffusion disk 25, passes over the stock solution diffusion disk 25, and is introduced into the separation zone of the high centrifugal field at a uniform flow rate.

[0084] In this case, since there is almost no settling distance between the raw liquid supply position and the vicinity of the inner circumferential surface of the rotary bowl where the concentrated liquid settles, the separated liquid and the concentrated liquid can be separated efficiently.

[0085] The stirring blade 29 provided at the outer periphery of the stock solution-diffusing disc prevents solid matter from being deposited on the inner periphery of the rotary bowl 16.

[0086] The separated liquid then clarifies as it swirls and rises between the body 17a of the screw conveyor 17 and the tip of the screw blade 17b, moves to the other end of the rotating bowl 16, passes through the through-hole 47 formed in the disk body 31 and the through-hole 19 formed in the other side wall 16c of the rotating bowl 16, and is discharged into the separated liquid discharge chamber 46 outside the rotating bowl 16, with the internal pressure adjusted by the separated liquid control valve 41, and is then discharged to the outside from the discharge port 46a.

[0087] The concentrated liquid reaches the vicinity of the inner peripheral surface of the rotating bowl 16, where particles larger than the classification particle size settle and form a cake. The concentrated liquid is concentrated as it moves toward the concentrated liquid discharge side by the screw blades 17b of the screw conveyor 17, which rotates at a desired rotational speed difference with respect to the rotating bowl 16. The concentrated liquid is then introduced into the skimming hole 32 by the internal pressure generated by adjusting the separated liquid control valve 41, and passes through the concentrated liquid discharge hole 30. The flow rate is adjusted by the concentrated liquid concentration adjusting device 35 or the constant-volume discharge pump 34 via a rotary joint (rotary joint, mechanical seal, etc.) 33, and the concentrated liquid is discharged outside the machine while being controlled to a predetermined concentration.

[0088] The concentrated liquid is fluidized by the stirring blades 48 provided near the opening of the skimming portion on the outer circumferential surface of the disk body 31, which facilitates smooth discharge.

[0089] According to the present invention, the device is sealed, the discharge rate of concentrated liquid can be controlled, continuous operation is possible, and the raw liquid can be uniformly supplied from a position close to the inner circumferential surface of the rotating bowl where the centrifugal effect is greatest. This reduces turbulence of the supplied liquid and minimizes the settling distance, resulting in excellent separation performance and allowing concentration and separation to proceed smoothly.

[0090] Furthermore, according to the present invention, since there is no seal between the rotary bowl and the screw conveyor, it is possible to provide a trouble-free centrifugal concentrator.

[0091] It also makes it possible to achieve highly precise wet classification down to submicron levels. [Example]

[0092] (3.1. Description of another centrifugal concentrator of the present invention) (double-supported structure type)

[0093] A second embodiment of the present invention will be described with reference to FIGS.

[0094] The centrifugal concentrator of the second embodiment of the present invention has a screw conveyor with a double-supported structure and uses a seal such as an oil seal. The same components as those in the first embodiment are designated by the same reference numerals and will not be described.

[0095] As shown in Figures 5 and 6, the centrifugal concentrator of the second embodiment of the present invention comprises a cylindrical rotating bowl 49 that rotates at high speed around an axis, a screw conveyor 50 that is coaxially arranged within this rotating bowl 49 and moves sediment (concentrated liquid) that has accumulated (settled) on the inner surface (inner wall surface) of the rotating bowl 49 from one side to the other in the axial direction, a raw liquid supply section, a concentrated liquid discharge section, and a separated liquid discharge section, and the raw liquid supply section supplies the raw liquid from a position close to the inner surface of the rotating bowl 49 (a level position near the tip of the screw conveyor blades).

[0096] While the first embodiment has a cantilever structure, the second embodiment of the present invention has a double-supported structure, and the basic configuration is the same as that of the first embodiment.

[0097] The configuration of the second embodiment of the present invention will be specifically described below.

[0098] The rotating bowl 49 comprises, for example, a cylindrical main body 49a having a circular inner cross-sectional shape, one and the other side walls 49b, 49c that close one and the other openings of the cylindrical main body 49a, and support shafts 51, 52 that protrude outward from the axial center of each side wall and have axially extending through holes 51a, 52a that communicate with the interior of the rotating bowl 49, and the support shafts 51, 52 are rotatably supported by bearings 53a, 53b and are configured to rotate at high speed by a rotating means (not shown) such as a motor connected to a pulley 54 fixed to the support shaft 51.

[0099] The screw conveyor 50 comprises a cylindrical body 50a provided within the rotating bowl 49, a spiral screw blade 50b provided on the outer peripheral surface of the body 50a from one end to the other with its tip close to the inner peripheral surface (inner peripheral wall) of the rotating bowl 49, one rotating shaft 55 provided so as to protrude outward from the axial center of one side of the body 50a, and the other rotating shaft 56 provided so as to protrude outward from the axial center of the other side of the body 50a, and the tip portion of the screw blade 50b is formed so as to be close to the inner peripheral surface (inner peripheral wall) of the rotating bowl 49.

[0100] Furthermore, one rotating shaft 55 and the other rotating shaft 56 of the body portion 50a extend outward through the through holes 51a and 52a of the one and other support shafts 51 and 52, respectively, and are rotatably supported by bearings 53c and 53d. For example, they are configured to rotate by a rotating means (not shown) such as a motor connected to a pulley 57 fixed to the rotating shaft 55, thereby rotating the body portion 50a.

[0101] In addition, a seal such as an annular oil seal 58 is provided between the rotary bowl 49 and the screw conveyor 50.

[0102] The raw liquid supply section comprises, for example, a raw liquid supply hole 59 extending axially from one end of one of the rotating shafts 55 to the base of the rotating shaft 55, one or more raw liquid discharge holes 60 that communicate with the other end of the raw liquid supply hole 59, extend radially to the outer circumferential surface of the rotating shaft 55, and communicate with the inside of the rotating bowl 49, and raw liquid introduction means that introduces the raw liquid from the raw liquid discharge hole 60 into a position close to the inner circumferential surface of the rotating bowl 49 (the position of the tip portion of the screw blade 50 b), and for example, comprises a disk-shaped raw liquid diffusion disk 25 that is provided coaxially on the outer circumferential surface of one end side of the body portion 50 a of the screw conveyor 50, and whose outer circumferential surface is close to the inner circumferential surface of the rotating bowl 49.

[0103] Further, an agitating blade 29 is provided on the outer circumferential surface of the stock solution-diffusing disk 25 .

[0104] One end of the stock solution supply hole 59 is connected to a stock solution supply means, for example, a stock solution supply pipe 27 connected to a stock solution metering pump 26, via a sealing means such as a rotary joint (mechanical seal) 28. The stock solution supplied from the stock solution supply pipe 27 passes through the stock solution supply hole 59, and is then moved by the stock solution diffusion disk 25 between the side wall of the rotating bowl 49 and the side surface of the stock solution diffusion disk 25, and is supplied from an input opening between the inner surface of the rotating bowl 49 and the stock solution diffusion disk 25 to a level position near the tip of the screw blade 50b.

[0105] The concentrated liquid discharge section comprises, for example, a concentrated liquid discharge pipe 62 formed coaxially within a separated liquid discharge hole 61 formed to extend axially from the other end of the rotating shaft 56 to the other end of the body portion 50a and protruding outward from the other end opening of the separated liquid discharge hole 61, and a skimming section that introduces the concentrated liquid near the inner peripheral surface of the rotating bowl 49 into the concentrated liquid discharge pipe 62. The skimming section comprises, for example, a disk body 31 provided coaxially on the outer peripheral surface of the other end side of the body portion 50a and formed so that its outer peripheral surface is close to the inner peripheral surface of the rotating bowl 49, and one or more skimming holes 32 formed in the disk body 31, which communicate with one end of the concentrated liquid discharge pipe 62 and open radially to the outer peripheral surface.

[0106] The disk body 31 is formed with a through hole 47 for discharging the separated liquid.

[0107] Further, a stirring blade 48 is provided on the outer peripheral surface of the disk body 31 in the vicinity of the opening of the skimming portion at one location or at a plurality of locations spaced apart at desired distances in the circumferential direction.

[0108] The concentrated liquid near the inner surface of the rotating bowl 49 is introduced into the skimming holes 32 from the outer surface of the disk body 31, and then discharged out of the rotating bowl 49 through the concentrated liquid discharge pipe 62 by a concentrated liquid metering discharge pump 34 connected to the other end of the concentrated liquid discharge pipe 62 via a rotary joint 33 (rotary joint, mechanical seal) or the like.

[0109] Instead of using the rotary joint 33 and the pump 34, a concentrated liquid concentration adjusting device 35 may be provided.

[0110] The separated liquid discharge section is, for example, composed of a separated liquid discharge hole 61 formed in the other rotating shaft 56, a separated liquid introduction hole 63 at one or more locations that communicates with one end of the separated liquid discharge hole 61, extends radially to the outer circumferential surface of the body section 50a, and is formed to communicate with the hole 47, and a pressure adjustment means composed of a separated liquid control valve 41 provided at an opening 64 between the separated liquid discharge hole 61 and the concentrated liquid discharge pipe 62, for controlling the opening size of the opening and maintaining an internal pressure that allows the concentrated liquid to be discharged from the skimming section.

[0111] As the pressure adjusting means, for example, as in the first embodiment, there is a method of adjusting the opening and closing of the valve by a spring or electric motor to control the opening amount of the opening.

[0112] A separated liquid discharge chamber 46 having a discharge port 46 a that covers the opening and the separated liquid control valve 41 may be provided on the outer surface of the other side wall 49 c of the rotary bowl 49 .

[0113] The separated liquid near the surface of the body is then discharged through the through-hole 47, from the separated liquid inlet hole 63, and from the opening 64 between the separated liquid outlet hole 61 and the concentrated liquid outlet pipe 62, and the separated liquid control valve 41 maintains an internal pressure that allows the concentrated liquid to be discharged from the skimming section.

[0114] (3.2. Explanation of the Function of Example 2)

[0115] Example 2 is operated in the same manner as Example 1, and the raw liquid can be uniformly supplied from a position close to the inner surface of the rotating bowl where the centrifugal effect is greatest, which reduces turbulence in the supply liquid and minimizes the settling distance, resulting in excellent separation performance and promoting concentration and separation.

[0116] (4. Schematic diagram of the sinking state between the present invention and conventional machines and explanation of the comparison of simulation calculations using theoretical formulas)

[0117] The performance of the raw liquid supply method (the present invention) in which the raw liquid is fed from the tip of the screw blade is compared with the raw liquid supply method (the conventional machine) in which the raw liquid is fed from the outer periphery of the screw conveyor body.

[0118] (4.1. Description of the present invention)

[0119] (1) Explanation of the principle of the present invention

[0120] As shown in Figures 7 to 10, the centrifugal effect is greatest at the tip of the screw conveyor blade where the raw liquid is fed, and the separation circumferential area is largest, resulting in the smallest particle size for classification. Furthermore, the settling distance is smallest at this position, and particles larger than the smallest particle size for classification instantly reach the inner circumferential surface of the rotating bowl and become a concentrated liquid.

[0121] Particles smaller than the minimum classification particle size rise (move toward the center) along with the separated liquid, pass through through-holes 47 located on the surface of the body of the screw conveyor, and are discharged outside the machine from separated liquid discharge hole 61.

[0122] The volume of the separated liquid was calculated by subtracting the volume of the concentrated liquid from the volume of the undiluted liquid, and the classified particle size at each level position (distance from the central axis) described below was calculated from the linear velocity of the ascending flow of the separated liquid at this volume.

[0123] As one moves from the outer periphery to the inner periphery, the centrifugal effect decreases, and the separation circumferential area becomes smaller, resulting in an increase in the classified particle size. However, particles larger than the minimum particle size at the tip of the screw conveyor blade are already almost entirely captured in the concentrated liquid, with little leakage into the separated liquid.

[0124] This is the advantage of adding the raw liquid from the tip of the screw blade.

[0125] (2) Explanation of the simulation of the present invention

[0126] The raw liquid is supplied at 200 L / h from the tip of the screw blades, dt (diameter) = 0.34 m, and the concentrated liquid that immediately settles near the inner surface of the rotating bowl is discharged outside the machine at 50 L / h. The remaining separated liquid, 150 L / h, rises through the separation zone formed between the tip of the screw blades, dt = 0.34 m, and the screw body, dt = 0.17 m, and is discharged from the separated liquid discharge pipe (4x concentrated).

[0127] The upward flow linear velocity of the separated liquid at each X position during the upward movement was substituted into the Stokes equation (Equation 1) to simulate and calculate the classified particle size, which is shown in Table 1.

[0128]

number

[0129] [Table 1]

[0130] From Table 1, the classification particle size is 0.44 microns when the diameter d is 0.34 m. Particles larger than 0.44 microns are captured in the concentrated liquid side immediately after the raw liquid is added, and particles smaller than 0.44 microns are discharged from the separated liquid side.

[0131] The dimensions, symbols, and units used in the simulation of the present invention are shown in FIGS. 11 and 12.

[0132] (4.2. Description of conventional models)

[0133] (1) Explanation of the principle of the conventional machine

[0134] The conditions for the comparison were the same as those of the machine of the present invention, except for the position of the raw liquid supply.

[0135] As shown in Figures 13 to 15, the raw liquid is supplied from the body of the screw conveyor where the centrifugal effect is minimal.

[0136] Theoretically, particles on the surface of the screw conveyor barrel that are smaller than the settling particle diameter are discharged as separated liquid. However, in reality, the raw liquid supply port and the separated liquid discharge port are located at the same screw barrel diameter level, which makes it easy for the raw liquid and separated liquid to mix, and particles larger than the settling particle diameter are easily caught in the separated liquid, resulting in a poor recovery rate.

[0137] Particles larger than the settling particle diameter on the surface of the screw conveyor body are separated by settling over the long settling distance from the outer periphery of the screw body to the tip of the screw, and are discharged as a concentrated liquid.

[0138] The diameter of each settling particle was calculated by calculating the downward linear velocity at each level position from the volume of concentrated liquid obtained by subtracting the volume of separated liquid from the volume of raw liquid, and then substituting this value into the Stokes equation (Equation 2) as described below.

[0139]

number

[0140] (2) Explanation of the simulation of the conventional machine

[0141] During concentration, particles settle from the surface of the screw conveyor body, where the centrifugal effect is low, to the tip of the screw blade, resulting in a long settling distance. A simulation was conducted to calculate the situation when 200 L / h of raw liquid was fed in, the separated liquid was discharged from the separated liquid discharge pipe along the screw conveyor body at 150 L / h, and the concentrated liquid settled from the outer periphery of the screw body toward the inner wall of the bowl outer periphery at 50 L / h (4x concentration), as shown in Table 2.

[0142] [Table 2]

[0143] The diameter of the settling particles at the raw liquid input position db (diameter) = 0.17 m in the body of the screw conveyor was 0.51 microns. As the diameter approached the tip of the screw blade dt = 0.34 m, the diameter of the settling particles became smaller, ultimately reaching 0.25 microns. At the raw liquid input position db = 0.17 m, the separated liquid would theoretically contain particles smaller than 0.51 microns, but because the separated liquid outlet has the same diameter as the raw liquid supply position, some of the raw liquid can easily become entrained, and coarse particles can easily become mixed into the separated liquid.

[0144] The dimensions, symbols, and units used in the simulation of the conventional machine are shown in Figures 12 and 16. The other dimensions, symbols, and units are the same as those of the machine of the present invention.

[0145] (4.3. Simulation Results) (Summary)

[0146] (1) The present invention

[0147] The radial particle size of the classified particles was determined when the raw liquid was supplied from the tip of the screw blade, the separated liquid was discharged from the body of the screw conveyor, and the concentrated liquid was discharged from the raw liquid supply position (Table 1).

[0148] The feed position of the raw liquid is where the centrifugal effect and separation circumferential area are maximum and the sedimentation distance is minimum, so the smallest classified particle size is obtained at this position. Compared to the feed amount of raw liquid, the separated liquid (excluding the concentrated liquid) has a liquid volume that rises toward the body of the screw conveyor, where the centrifugal effect and separation circumferential area decrease, and as the separated liquid rises, the classified particle size increases. However, as the concentrated liquid, particles 0.44 microns or larger are almost instantly captured at the tip of the screw conveyor blade, so there is almost no mixing of particles 0.44 microns or larger into the separated liquid.

[0149] (2) Conventional model

[0150] The radial settling particle size was determined when the raw liquid was supplied from the screw conveyor body, the separated liquid was discharged from the same screw conveyor body, and the concentrated liquid was discharged from the tip of the screw blade (Table 2).

[0151] When the raw liquid is fed from the body of the screw conveyor, it is separated in a low centrifugal field, and 0.51 microns is obtained from Equation 2. Particles with a particle size of 0.51 microns or more become concentrated liquid, and particles smaller than 0.51 microns are discharged as separated liquid.

[0152] The volume of concentrated liquid is small compared to the volume of separated liquid, and as the concentrated liquid flows downward, the downward linear velocity decreases, and theoretically the settling particle size of the concentrated liquid becomes smaller. However, the feed position of the raw liquid is at the body of the screw conveyor, which is the same position as the discharge level of the separated liquid, and this position has the lowest centrifugal effect and the smallest separation circumferential area, making it susceptible to the influence of the flow of the raw liquid. The settling of fine particles larger than the settling particle size is also easily hindered, and these fine particles are easily entrained in the separated liquid, and the length of the settling distance also affects the recovery rate, so that in addition to particles smaller than 0.51 microns, larger particles are also discharged from the separated liquid side due to the influence of entrainment. [Explanation of symbols]

[0153] 1 Rotating Bowl 1a Cylindrical body 1b side wall 1c side wall 2 Support shaft 2a Through hole 2b pulley 3 Support shaft 3a Through hole 4. Screw conveyor 4a Torso 4b screw blade 5 One rotation axis 5a pulley 6 The other rotation axis 7a Bearing 7b Bearing 7c bearing 7d Bearing 8 Stock solution supply hole 9 Stock solution drain hole 10 Separated liquid drain hole 10a Other end opening 11 Separated liquid introduction hole 12 Concentrate discharge pipe 12a Other end opening 13 Skimming tube 14 Concentrate concentration adjustment device 15 Oil seal 16 Rotating Bowls 16a Cylindrical main body 16b side wall 16c side wall 17 Screw conveyor 17a Body part 17b Screw blade 18 Support shaft 18a Through hole 19 Through hole 20 Bearings 21 Pulley 22 Rotation axis 23 Bearings 24 pulleys 25 Undiluted solution diffusion disc 26. Concentrated liquid supply pump 27 Stock solution supply pipe 28 Rotary Joint 29 Mixing blade 30 Concentrate drain hole 31 Disk 32 Skimming hole 33 Rotary joint 34 Concentrated liquid metering discharge pump 35 Concentrate concentration adjustment device 36 Stepping motor section 37 Rotation axis 38 Threaded part 39 Main body 40 Valve body 41 Separation liquid control valve 42 Cone 42a Other end surface 43 Through hole 44 Tsuba 45 spring 46 Separated liquid discharge chamber 46a Outlet 47 Through hole 48 stirring blade 49 Rotating Bowl 49a Cylindrical body 49b One side wall 49c Other side wall 50 screw conveyor 50a Body 50b screw blade 51 Support shaft 51a Through hole 52 Support shaft 52a through hole 53a Bearing 53b Bearing 53c bearing 53d bearing 54 Pulley 55 Rotation axis 56 Rotation axis 57 Pulley 58 Oil seal 59 Stock solution supply hole 60 Stock solution discharge hole 61 Separated liquid drain hole 62 Concentrate discharge pipe 63 Separated liquid introduction hole 64 Opening

Claims

1. a cylindrical rotating bowl that is rotatably provided; a screw conveyor provided within the rotating bowl, which moves the concentrated liquid that has settled on the inner circumferential surface of the rotating bowl from one side to the other in the axial direction, the screw conveyor having a tip end of a screw blade provided close to the inner circumferential surface of the rotating bowl; a rotating means for rotating the rotating bowl and the screw conveyor, respectively; a raw liquid supply unit provided on one side of the rotating bowl and configured to supply raw liquid containing fine particles from the outside to the inside of the rotating bowl; a concentrated liquid discharge section provided on the other side of the rotating bowl, which discharges the concentrated liquid that has settled on the inner circumferential surface of the rotating bowl due to centrifugal force caused by rotation of the rotating bowl and has been moved by the screw conveyor from inside the rotating bowl to the outside; a separated liquid discharge section that discharges the clarified separated liquid from the rotating bowl to the outside by centrifugal force caused by the rotation of the rotating bowl, The rotating bowl comprises a cylindrical body, one and the other side walls that close one and the other openings of the cylindrical body, a support shaft provided on the one side wall so as to protrude outward, and a through hole formed in the other side wall, a rotation shaft of the screw conveyor formed only on the other end side of the body of the screw conveyor, the rotation shaft passing through a through hole formed in the other side wall of the rotary bowl, protruding outward, and being rotatably supported in a cantilever manner; the raw liquid supply unit has a through hole extending in the axial direction from one end of the support shaft connected to raw liquid supply means for supplying raw liquid at a desired pressure, penetrating one side wall of the rotating bowl, and communicating with the inside of the rotating bowl, and raw liquid introduction means formed to introduce the raw liquid from the through hole of the support shaft to a position close to the inner circumferential surface of the rotating bowl, the raw material introduction means is a raw material diffusion disk provided on the outer peripheral surface of one end of the body of the screw conveyor, the outer peripheral surface of which is close to the inner peripheral surface of the rotating bowl, the concentrate-liquid-diffusing disc allows the concentrate to be introduced into a position in the rotary bowl close to the inner peripheral surface thereof through a gap between the outer peripheral surface of the concentrate-liquid-diffusing disc and the inner peripheral surface of the rotary bowl; the concentrated liquid discharge section comprises a concentrated liquid discharge hole formed in the rotation shaft at the other end of the screw conveyor, the concentrated liquid being connected to a means for adjusting the discharge amount of the concentrated liquid, and a skimming section for introducing the concentrated liquid that has settled on the inner peripheral surface of the rotary bowl into the concentrated liquid discharge hole; the skimming section comprises a disk provided on the outer peripheral surface of the other end side of the screw conveyor, the outer peripheral surface of which is formed to be close to the inner peripheral surface of the rotating bowl, and a skimming hole provided on the disk, which communicates with one end of the concentrated liquid discharge hole and opens to the outer peripheral surface in the radial direction, a pressure adjusting means for adjusting the opening size of the opening to adjust the pressure inside the rotating bowl;

2. 2. A centrifugal concentrator without an oil seal as described in claim 1, characterized in that stirring blades are provided at one location on the outer peripheral surface of the raw liquid diffusion disk or at multiple locations spaced a desired distance apart in the circumferential direction to prevent the supplied raw liquid from adhering to the inner peripheral surface of the rotating bowl.

3. a cylindrical rotating bowl that is rotatably provided; a screw conveyor provided within the rotating bowl, which moves the concentrated liquid that has settled on the inner circumferential surface of the rotating bowl from one side to the other in the axial direction, the screw conveyor having a tip end of a screw blade provided close to the inner circumferential surface of the rotating bowl; a rotating means for rotating the rotating bowl and the screw conveyor, respectively; a raw liquid supply unit provided on one side of the rotating bowl and configured to supply raw liquid containing fine particles from the outside to the inside of the rotating bowl; a concentrated liquid discharge section provided on the other side of the rotating bowl, which discharges the concentrated liquid that has settled on the inner circumferential surface of the rotating bowl due to centrifugal force caused by rotation of the rotating bowl and has been moved by the screw conveyor from inside the rotating bowl to the outside; a separated liquid discharge section that discharges the clarified separated liquid from the rotating bowl to the outside by centrifugal force caused by the rotation of the rotating bowl, the raw liquid supply unit has a raw liquid introduction means that introduces the raw liquid into a position close to the inner circumferential surface of the rotating bowl, the raw material introduction means is a raw material diffusion disk provided on the outer peripheral surface of one end side of the body portion of the screw conveyor, the outer peripheral surface of which is close to the inner peripheral surface of the rotating bowl, the concentrate-liquid-diffusing disc allows the concentrate to be introduced into a position in the rotary bowl close to the inner peripheral surface thereof through a gap between the outer peripheral surface of the concentrate-liquid-diffusing disc and the inner peripheral surface of the rotary bowl; A centrifugal concentrator characterized in that stirring blades are provided at one location on the outer peripheral surface of the raw liquid diffusion disk or at multiple locations spaced a desired distance apart in the circumferential direction to prevent the supplied raw liquid from adhering to the inner peripheral surface of the rotating bowl.

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