Disk-type centrifuge and method for separating processed materials

Abstract

The present invention provides a disc-type centrifuge that can discharge even highly viscous light phases separated from processed materials without any problems. [Solution] In a disc-type centrifugal separator 1 configured such that a bowl 2 and a number of separation disks 12 arranged in a separation chamber 21 rotate at high speed together with a rotating shaft 11, and the heavy phase that has moved to the radially outer region of the separation chamber 21 and the light phase that has moved to the radially inner region are discharged separately, two centripetal pumps 5A and 5B are arranged in series in the vertical direction above the bowl 2, the lower centripetal pump 5A is in communication with the separation chamber 21 and is configured to receive the light phase from the separation chamber 21, and the upper centripetal pump 5B is in communication with the lower centripetal pump 5A and is configured to receive the light phase that has overflowed from the lower centripetal pump 5A.

Description

Technical Field

[0001] The present invention relates to a disk-type centrifuge configured to stack a large number of conical separation disks in a bowl and rotate them at high speed to separate a processed material supplied into the bowl, and a method for separating a processed material using this disk-type centrifuge.

Background Art

[0002] As one of centrifuges that separate a processed material using centrifugal force, there is known a centrifuge (disk-type centrifuge) in which a large number of conical separation disks are stacked in a bowl and rotated at high speed to apply centrifugal force to the processed material.

[0003] FIG. 3 is a cross-sectional view schematically showing the internal structure of a conventional general disk-type centrifuge 1. In this disk-type centrifuge 1, a bowl 2 having an upper half formed in a conical shape is disposed within a casing 3, and a large number of conical separation disks 12 are disposed in the bowl 2 in a stacked state while forming a slight gap. The bowl 2 is coupled to the upper end of a vertically disposed rotating shaft 11 that penetrates the bottom of the casing 3 (casing bottom 31), and the bowl 2 and the built-in separation disks 12 are configured to rotate at high speed by a rotational driving force supplied to the rotating shaft 11 from a motor (not shown).

[0004] Then, when the stock solution of the processed material is introduced from the stock solution supply pipe 13 disposed above the bowl 2 into the space (separation chamber 21) within the bowl 2, due to the action of centrifugal force, the components with a large density (heavy phase, for example, solid sludge, heavy liquid, etc.) in the processed material move to the radially outer region S1 within the separation chamber 21, and the components with a small density (light phase, for example, clarified liquid, light liquid, etc.) move to the radially inner region S2 within the separation chamber 21, and they can be discharged through individual paths.

[0005] More specifically, the heavy phase that moves to region S1 within the separation chamber 21 and accumulates can be instantly discharged to the outside of bowl 2 by operating the heavy phase discharge mechanism, which includes a movable bottom plate 4 that partitions the lower side of the separation chamber 21, while the disk-type centrifuge 1 is in operation, that is, while bowl 2 is rotating at high speed. The light phase that moves to region S2 within the separation chamber 21 can be continuously discharged to the outside of the machine by a centripetal pump 5 located above bowl 2 and a light phase discharge pipe 15 located further above it.

[0006] The centripetal pump 5 is a type of centripetal pump that discharges a rapidly swirling fluid using its kinetic energy. As shown in Figure 4, it consists of a cylindrical portion 51 that largely surrounds the outside of the raw liquid supply pipe 13 and a hollow flange portion 53 that is located inside the cylindrical portion 51.

[0007] The cylindrical portion 51 is positioned concentrically with the bowl 2 (see Figure 3) and fixed to the upper end of the bowl 2, and is configured to rotate at high speed together with the bowl 2. The cylindrical portion 51 is formed by partitions on the outer circumference, upper side, and lower side, and is configured to store fluid along the inner circumference due to the centrifugal force acting during rotation. A circular opening 52 is formed in the center of the partition on the lower side, as shown in Figure 4, and the internal space of the cylindrical portion 51 is in communication with the separation chamber 21 (region S2) (see Figure 3) of the bowl 2 through this circular opening 52.

[0008] The hollow flange portion 53 is fixed to the raw liquid supply pipe 13, and is positioned so that its outer surface is at a certain distance radially inward from the inner surface of the cylindrical portion 51, so as not to come into contact with the rapidly rotating cylindrical portion 51. As shown in Figure 4, multiple inlets 54 (four in the example in Figure 4) for taking in the light phase are formed on the outer surface of this hollow flange portion 53.

[0009] As shown in Figure 5, inside the hollow flange portion 53, there is an annular channel 55 that circles the outside of the raw liquid supply pipe 13, and multiple curved channels 56 (the same number as the inlet 54) that guide the light phase taken in from the inlet 54 to the radially inward annular channel 55 (connecting the inlet 54 and the annular channel 55). These curved channels 56 are each formed between multiple fixed vanes 57 formed inside the hollow flange portion 53.

[0010] The curved channel 56 and the fixed vane 57 have a radially outer portion (the portion near the inlet 54) that extends in a direction in which the light phase can easily flow in (a direction in which the angle difference with the direction of light phase travel is small (for example, 30° or less)), and from there toward the radially inward portion (from the inlet 54 side toward the annular channel 55 side), the shape is curved so that the angle with respect to the radial direction gradually decreases.

[0011] The light phase discharge pipe 15 is arranged concentrically with the raw liquid supply pipe 13 so as to cover the outside of the raw liquid supply pipe 13, and its lower end is connected to the hollow flange portion 53. A certain gap is formed between the inner circumferential surface of the light phase discharge pipe 15 and the outer circumferential surface of the raw liquid supply pipe 13. This gap between the light phase discharge pipe 15 and the raw liquid supply pipe 13 communicates with the annular flow path 55 inside the hollow flange portion 53 at its lower end.

[0012] To briefly explain the operation of the centripetal pump 5, the cylindrical portion 51 is in communication with the separation chamber 21 (region S2) (see Figure 3) of the bowl 2 via the opening 52, as described above. Therefore, the light phase that has moved to region S2 as the separation process progresses will sequentially flow into the cylindrical portion 51 from the opening 52. The light phase that has flowed into the cylindrical portion 51 rotates at high speed together with the bowl 2 and the cylindrical portion 51, and due to the action of centrifugal force, it swirls in region S3 (the region shown by the dashed line in Figure 4) along the inner circumferential surface of the cylindrical portion 51.

[0013] As shown in Figure 4, the hollow flange portion 53 is configured such that its outer circumference contacts (is submerged in) the light phase swirling in region S3 of the cylindrical portion 51, and as described above, the curved flow channel 56 and the portion near the inlet 54 of the fixed vane 57 extend in a direction that allows the light phase to flow in easily. Therefore, a portion of the light phase swirling in region S3 is taken into the hollow flange portion 53 from the inlet 54, passes through the curved flow channel 56, and flows into the annular flow channel 55.

[0014] The annular channel 55 is in communication with the inside of the light phase discharge pipe 15 (the gap between it and the raw liquid supply pipe 13). When light phase flows continuously from the region S3 of the cylindrical part 51 into the hollow flange part 53, the light phase flowing in the annular channel 55 is pushed out by the subsequent light phase and enters the inside of the light phase discharge pipe 15. Further pressed by the subsequent light phase, it is continuously discharged outside the machine through the light phase discharge pipe 15. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Japanese Unexamined Patent Publication No. 56-108550 [Patent Document 2] Japanese Patent Publication No. 2019-107622 [Patent Document 3] Japanese Patent Publication No. 2024-32074 [Patent Document 4] Publication No. 6-28196 [Overview of the project] [Problems that the invention aims to solve]

[0016] When performing separation using a conventional disk-type centrifuge 1 as shown in Figure 3, if the separated light phase (separated liquid, etc.) has high viscosity, the centripetal pump 5 may not be able to keep up with the discharge of the light phase. In other words, the discharge rate of the light phase by the centripetal pump 5 decreases, and may fall below the amount of light phase flowing from the separation chamber 21 into the cylindrical section 51. In this case, the light phase overflows from the upper opening of the cylindrical section 51 (between the cylindrical section 51 and the light phase discharge pipe 15), making it impossible to discharge (recover) it through the proper route.

[0017] To address these issues, one could consider increasing the size of the centripetal pump 5, that is, adopting a centripetal pump with a larger diameter. However, in this case, the entire system would become larger, the discharge power would increase, and the cost benefits would be lost.

[0018] The present invention aims to solve the problems of the prior art and provides a disk-type centrifuge that can discharge even when the light phase separated from the processed material has high viscosity without any problems. [Means for solving the problem]

[0019] The disk-type centrifuge according to the present invention is configured such that a bowl placed inside a casing and a number of conical separation disks placed in the separation chamber of the bowl in a stacked state with gaps between them rotate at high speed with a vertically positioned rotation axis, and by the action of centrifugal force, the heavy phase in the material supplied to the separation chamber moves to the radially outer region of the separation chamber, and the light phase moves to the radially inner region of the separation chamber, and the heavy phase and light phase are discharged through separate paths, and at least two centripetal pumps are arranged in series in the vertical direction above the bowl, the lower centripetal pump is in communication with the separation chamber and is configured to receive the light phase from the separation chamber, and the upper centripetal pump is configured to receive the light phase that overflows from the lower centripetal pump.

[0020] In this disk-type centrifuge, two light-phase discharge pipes are arranged in a double layer outside the stock solution supply pipe. The inner light-phase discharge pipe is connected such that the gap between it and the stock solution supply pipe communicates with the inside of the lower centripetal pump. Preferably, the outer light-phase discharge pipe is connected such that the gap between it and the inner light-phase discharge pipe communicates with the inside of the upper centripetal pump.

[0021] Also, the lower centripetal pump has a cylindrical part arranged to surround the outside of the stock solution supply pipe and a hollow flange part arranged inside the cylindrical part. The cylindrical part is arranged concentrically with the bowl, fixed to the upper end part of the bowl, and has parts for partitioning the outer peripheral side, the upper side, and the lower side, and is configured to be able to store fluid along the inner peripheral surface by the centrifugal force acting during rotation. The hollow flange part is fixed to the stock solution supply pipe, and an inlet for taking the light phase into the inside is formed on the outer peripheral surface, and an annular flow path and a curved flow path for guiding the light phase taken in from the inlet to the annular flow path on the radially inner side are formed inside. This is preferable.

[0022] Furthermore, the upper centripetal pump has a cylindrical part arranged to surround the outside of the inner light-phase discharge pipe and a hollow flange part arranged inside the cylindrical part. The cylindrical part is arranged concentrically with the bowl, fixed to the upper end part of the cylindrical part of the lower centripetal pump, and has parts for partitioning the outer peripheral side, the upper side, and the lower side, and is configured to be able to store fluid along the inner peripheral surface by the centrifugal force acting during rotation. The hollow flange part is fixed to the inner light-phase discharge pipe, and an inlet for taking the light phase into the inside is formed on the outer peripheral surface, and an annular flow path and a curved flow path for guiding the light phase taken in from the inlet to the annular flow path on the radially inner side are formed inside. This is preferable.

[0023] Also, preferably, the inner light-phase discharge pipe and the outer light-phase discharge pipe are connected to one light-phase recovery means and are configured such that the light phases discharged individually through them are mixed.

[0024] However, when using this disk-type centrifuge, by setting or adjusting the supply amount of the processed material into the separation chamber so that the inflow amount of the light phase from the separation chamber to the centripetal pump on the lower side exceeds the discharge amount of the light phase by the centripetal pump on the lower side, the light phase overflowing from the centripetal pump on the lower side can be made to flow into the centripetal pump on the upper side, and the light phase can be discharged from the centripetal pump on the lower side and the centripetal pump on the upper side.

Advantages of the Invention

[0025] Even when the light phase (separation liquid, etc.) separated by the separation process has high viscosity, the disk-type centrifuge according to the present invention can discharge those light phases through an appropriate path and recover them without problems.

Brief Description of the Drawings

[0026] [Figure 1] FIG. 1 is a cross-sectional view showing the internal structure of the disk-type centrifuge 1 according to the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view near the centripetal pumps 5A and 5B of the disk-type centrifuge 1 shown in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view schematically showing the internal structure of a conventional general disk-type centrifuge 1. [Figure 4] FIG. 4 is a partial cross-sectional perspective view showing the internal structure of the centripetal pump 5 of the disk-type centrifuge 1 shown in FIG. 3. [Figure 5] FIG. 5 is a partial cross-sectional perspective view showing the internal structure of the centripetal pump 5 of the disk-type centrifuge 1 shown in FIG. 3.

Embodiments for Carrying Out the Invention

[0027] The present invention can be implemented as a "disk-type centrifuge," or as a "method for separating processed materials" using this disk-type centrifuge. Embodiments of the present invention will be described below with reference to the attached drawings. Figure 1 is a cross-sectional view showing the internal structure of the disk-type centrifuge 1 according to the present invention. This disk-type centrifuge 1 has the same basic configuration as the conventional disk-type centrifuge 1 shown in Figures 3 to 5, and performs the separation of processed materials by the same principle. Furthermore, the heavy phase can be discharged from the separation chamber 21 by a heavy phase discharge mechanism including a movable bottom plate 4, and the light phase can be discharged by a centripetal pump 5 and a light phase discharge pipe 15, etc.

[0028] A distinctive feature of this invention is that two centripetal pumps 5 (5A, 5B) are arranged in series in the vertical direction above the bowl 2, and two light phase discharge pipes 15 (15A, 15B) are arranged in a double configuration outside the raw liquid supply pipe 13. These points will be described in detail below.

[0029] Figure 2 is an enlarged cross-sectional view of the vicinity of the centripetal pumps 5A and 5B of the disk-type centripetal centrifuge 1 shown in Figure 1. Of the two centripetal pumps 5A and 5B and the two light phase discharge pipes 15A and 15B shown, the lower centripetal pump 5A and the inner light phase discharge pipe 15A have the same configuration and function as the conventional centripetal pump 5 and light phase discharge pipe 15 shown in Figures 4 and 5.

[0030] More specifically, the lower centripetal pump 5A is composed of a cylindrical portion 51A and a hollow flange 53A. The cylindrical portion 51A has parts that partition the outer circumference, upper side, and lower side, and is configured to store fluid along its inner circumference by centrifugal force. It is positioned to largely surround the outside of the raw liquid supply pipe 13 and is fixed to the upper end of the bowl 2. The hollow flange portion 53A is fixed to the raw liquid supply pipe 13 inside the cylindrical portion 51A, and an inlet 54A is formed on its outer circumference. Inside, an annular flow path 55A, a curved flow path 56A extending in a direction in which the light phase easily flows in, and a fixed vane (not shown) are formed.

[0031] The inner light phase discharge pipe 15A is arranged concentrically so as to cover the outside of the raw liquid supply pipe 13, and a certain gap is formed between the inner circumferential surface of the light phase discharge pipe 15A and the outer circumferential surface of the raw liquid supply pipe 13. This gap between the light phase discharge pipe 15A and the raw liquid supply pipe 13 communicates with the annular flow path 55A in the hollow flange portion 53A at its lower end.

[0032] Then, when the material to be processed is supplied into bowl 2 and the separation process is performed, the light phase moves to the radially inward region S2 (see Figure 1) of the separation chamber 21, flows sequentially into the cylindrical section 51A from the opening 52A, is taken into the hollow flange section 53A from the inlet 54A within the cylindrical section 51A, flows through the curved channel 56A and into the annular channel 55A, is pressed by the subsequent light phase, and is continuously discharged outside the machine through the gap between the light phase discharge pipe 15A and the raw liquid supply pipe 13 (inside the light phase discharge pipe 15A).

[0033] The upper centripetal pump 5B and the outer light phase discharge pipe 15B also have substantially the same configuration and function as the conventional centripetal pump 5 and light phase discharge pipe 15 shown in Figures 4 and 5.

[0034] Specifically, the upper centripetal pump 5B is composed of a cylindrical portion 51B and a hollow flange portion 53B located inside it, which have the same configuration as the cylindrical portion 51A and hollow flange portion 53A of the lower centripetal pump 5A. However, as shown in Figure 2, the cylindrical portion 51B is positioned to surround the outside of the light phase discharge pipe 15A and is fixed to the cylindrical portion 51A of the lower centripetal pump 5A. The hollow flange portion 53B is also fixed to the light phase discharge pipe 15A.

[0035] The outer light phase discharge pipe 15B is arranged concentrically to cover the outside of the light phase discharge pipe 15A, and a certain gap is formed between the inner circumferential surface of the light phase discharge pipe 15B and the outer circumferential surface of the light phase discharge pipe 15A. This gap between the light phase discharge pipe 15B and the light phase discharge pipe 15A communicates with the annular flow path 55B inside the hollow flange portion 53B at its lower end.

[0036] Furthermore, the cylindrical portion 51B of the upper centripetal pump 5B is in communication with the cylindrical portion 51A of the lower centripetal pump 5A through an opening 52B formed in the partition portion below. Therefore, in the disk-type centrifugal separator 1 of this embodiment, if the discharge of the light phase by the centripetal pump 5A cannot keep up and the light phase overflows from the cylindrical portion 51A (for example, if the processed material contains a highly viscous liquid and the separated light phase has high viscosity, or if the amount of processed material supplied into the separation chamber 21 is set or adjusted so that the amount of light phase flowing in from the separation chamber 21 to the lower centripetal pump 5A exceeds the amount of light phase discharged by the lower centripetal pump 5A), the light phase will flow into the cylindrical portion 51B of the centripetal pump 5B.

[0037] The light phase that flows into the cylindrical section 51B is then taken into the hollow flange section 53B from the inlet 54B, passes through the curved channel 56B, flows into the annular channel 55B, is pressed by the subsequent light phase, and is continuously discharged outside the machine through the gap between the light phase discharge pipe 15B and the light phase discharge pipe 15A (inside the light phase discharge pipe 15B).

[0038] The light phase discharge pipes 15A and 15B are connected to a single light phase storage tank (or other light phase recovery means) (not shown), and the light phase discharged individually through the light phase discharge pipes 15A and 15B will eventually be mixed.

[0039] As described above, even if the light phase (separated liquid, etc.) separated by the separation process has high viscosity, and the discharge of the light phase by the centripetal pump 5A cannot keep up, causing the light phase to overflow from the cylindrical section 51A, the disk-type centrifugal separator 1 according to the present invention can be allowed to flow into the upper cylindrical section 51B, and then discharged and recovered through an appropriate path by the upper centripetal pump 5B and the outer light phase discharge pipe 15B.

[0040] Furthermore, while the lower centripetal pump 5A of the disc-type centrifuge 1 (see Figure 1) in the above embodiment has the same size (diameter) as the centripetal pump of a conventional general-purpose disc-type centrifuge, if a smaller diameter centripetal pump (multi-stage small-diameter centripetal pump) is used as the lower centripetal pump 5A, and the separation of a normal material (a material in which the separated light phase is not high viscosity) is performed, and the light phase separated in the separation chamber 21 is discharged by the lower centripetal pump 5A and the upper centripetal pump 5B, the power consumption for discharging the light phase can be reduced compared to a conventional general-purpose disc-type centrifuge.

[0041] Furthermore, when separating materials that have the property of foaming and deteriorating upon discharge, conventional methods have involved adding an antifoaming agent to the material. However, by using the disc-type centrifugal separator 1 employing the multi-stage small-diameter centripetal pump described above, it is possible to reduce losses during discharge and suppress foaming. As a result, the addition of an antifoaming agent becomes unnecessary, allowing for the recovery of the light phase without compromising quality, and reducing power consumption.

[0042] In the above embodiment, two centripetal pumps 5A and 5B are arranged in series in two upper and lower stages, but it is also possible to configure the system so that three or more centripetal pumps are arranged in series in the vertical direction. [Explanation of symbols]

[0043] 1: Disk-type centrifuge, 2: Bowl, 3: Casing, 4: Movable bottom plate, 5, 5A, 5B: Centripetal pump, 11: Axis of rotation, 12: Separable disk, 13: Stock solution supply pipe, 15,15A,15B: Light phase discharge pipe, 21: Separation room, 31: Casing bottom, 51, 51A, 51B: Cylindrical part, 52,52A,52B: opening, 53, 53A, 53B: Hollow flange section, 54,54A,54B: Inlet, 55, 55A, 55B: Circular flow path, 56, 56A, 56B: Curved channel, 57: Fixed blades,

Claims

1. A method for separating materials using a disk-type centrifuge, A disc-type centrifuge is configured such that a bowl placed inside a casing and numerous conical separation disks stacked within the bowl's separation chamber, forming gaps, rotate at high speed on a vertically positioned axis. Due to the action of centrifugal force, the heavy phase in the material supplied to the separation chamber moves to the radially outer region of the chamber, and the light phase moves to the radially inner region of the chamber, allowing the heavy and light phases to be discharged through separate paths. At least two centripetal pumps are arranged vertically in series above the bowl, with the lower centripetal pump communicating with the separation chamber and receiving the flow of the light phase from the separation chamber, and the upper centripetal pump receiving the flow of the light phase overflowing from the lower centripetal pump. By setting or adjusting the amount of material supplied to the separation chamber so that the amount of light phase flowing from the separation chamber to the lower centripetal pump exceeds the amount of light phase discharged by the lower centripetal pump, the light phase overflowing from the lower centripetal pump is allowed to flow into the upper centripetal pump. A method for separating a processed material, characterized by discharging the light phase from a lower centripetal pump and an upper centripetal pump.

2. In a disk-type centrifuge, a bowl placed inside a casing and a number of conical separation disks stacked with gaps between them and placed in the separation chamber of the bowl are configured to rotate at high speed with a vertically positioned axis, and due to the action of centrifugal force, the heavy phase in the material supplied to the separation chamber moves to the radially outer region of the separation chamber, and the light phase moves to the radially inner region of the separation chamber, so that the heavy phase and light phase can be discharged through separate paths, At least two centripetal pumps are arranged in series vertically above the bowl. The lower centripetal pump is configured to communicate with the separation chamber and allow the light phase to flow in from the separation chamber. A disc-type centrifugal separator characterized in that the upper centripetal pump is configured to receive the light phase that overflows from the lower centripetal pump.

3. Two light phase discharge pipes are arranged in a double configuration outside the raw liquid supply pipe. The inner light phase discharge pipe is connected such that the gap between it and the stock supply pipe communicates with the inside of the lower centripetal pump. The disk-type centrifugal separator according to claim 2, characterized in that the outer light phase discharge pipe is connected such that the gap between it and the inner light phase discharge pipe communicates with the inside of the upper centripetal pump.

4. The lower centripetal pump has a cylindrical portion arranged to surround the outside of the stock supply pipe and a hollow flange portion arranged inside the cylindrical portion. The cylindrical portion is arranged concentrically with the bowl, fixed to the upper end of the bowl, and has parts that partition the outer circumference, upper side, and lower side, and is configured to store fluid along the inner circumference due to the centrifugal force acting during rotation. The disk-type centrifugal separator according to claim 2 or 3, characterized in that the hollow flange portion is fixed to the raw liquid supply pipe, an inlet for taking in the light phase is formed on the outer surface, and an annular flow path and a curved flow path that guides the light phase taken in from the inlet to the radially inner annular flow path are formed inside.

5. The upper centripetal pump has a cylindrical portion arranged to surround the outside of the inner light phase discharge pipe, and a hollow flange portion arranged inside the cylindrical portion. The cylindrical portion is arranged concentrically with the bowl and fixed to the upper end of the cylindrical portion of the lower centripetal pump. It has a section that divides the outer circumference, upper side, and lower side, and is configured to store fluid along the inner circumference due to the centrifugal force acting during rotation. The disk-type centrifugal separator according to claim 3, characterized in that the hollow flange portion is fixed to the inner light phase discharge pipe, an inlet for taking in the light phase is formed on the outer surface, and an annular flow path and a curved flow path that guides the light phase taken in from the inlet to the radially inner annular flow path are formed inside.

6. The disk-type centrifugal separator according to claim 3, characterized in that the inner light phase discharge pipe and the outer light phase discharge pipe are connected to a single light phase recovery means, and the light phases discharged individually through them are mixed.

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