JP2021030131A - Centrifugal separation apparatus - Google Patents

Abstract

To provide a centrifugal separation apparatus that is effective in stably maintaining a liquid layer, so that solid-liquid separation performance is hardly impaired.SOLUTION: The centrifugal separation apparatus comprises: an outer shell bowl 3 that rotates to centrifugally separate solid Sd and liquid Lq from undiluted solutions M, an inner shell part 41 arranged in the outer shell bowl 3, and a screw blade 42, provided on an outer peripheral surface 41a of the inner shell part 41, which transfers the solid Sd to one side along a rotation shaft line L of the inner shell part 41. The inner shell part 41 comprises emission ports 91 through which the undiluted solutions M therein are emitted to a space between an inner peripheral surface 3b of the outer shell bowl 3 and the inner shell part 41, where the emission ports 91 are arranged to point a front side in a rotation direction Ra with an emission direction Da of the undiluted solution M as a reference.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a centrifuge that centrifuges a solid and a liquid from a mixture of the solid and the liquid.

Patent Document 1 discloses a centrifuge device that centrifuges a solid and a liquid by centrifugation. The centrifuge comprises inner and outer tubular bodies having the same axis of rotation. The mixture to be centrifuged passes through the inner tubular body and is discharged into the outer tubular body through the outlet of the inner tubular body. The mixture is centrifuged in the outer tubular body, and the liquid separated from the solid forms a liquid layer that rotates following the inner peripheral surface of the outer tubular body. For example, a new mixture is released from the inner tubular body at a rotation speed similar to that of the outer tubular body, and this new mixture is centrifuged while rotating in the same direction as the outer tubular body. It also moves in the direction and mixes with the liquid layer.

Japanese Unexamined Patent Publication No. 2009-136790

However, the mixture discharged in the centrifugal direction from the rotating inner tubular body decreases in the rotational direction as the distance from the center of rotation decreases, and when mixed with the liquid layer, it rotates with the liquid layer. The speed difference tends to be large. As a result, the liquid layer may be disturbed due to this difference in rotation speed, and the solid-liquid separability for separating the solid and the liquid may be impaired.

It is an object of the present disclosure to provide a centrifuge device which is advantageous for stably maintaining a liquid layer separated from a solid and does not impair the solid-liquid separability.

The centrifuge device according to one aspect of the present disclosure includes a tubular outer body portion that accommodates a mixture of a solid and a liquid and centrifuges the solid and the liquid from the mixture by rotation, and an outer body portion inside the outer body portion. It is arranged along the rotation axis of the part to transfer the mixture, and is provided on the inner body part that rotates in the same direction as the rotation direction of the outer body part and the outer peripheral surface of the inner body part, and is provided on the rotation axis of the inner body part. It comprises a screw blade that transfers solids to one side along the side, and the inner body is provided with a discharge port that discharges an internal mixture between the inner peripheral surface of the outer body and the inner body. Are arranged facing forward in the rotational direction with respect to the discharge direction of the mixture.

According to this centrifuge, the mixture inside the inner body is discharged forward through the discharge port in the rotational direction. Therefore, the velocity in the rotation direction is substantially increased as compared with the mode in which the discharge is performed in the centrifugal direction. As a result, it becomes easy to reduce the speed difference in the rotation direction when the mixture is mixed with the liquid layer.

In some embodiments, the screw blades are spirally provided on the outer peripheral surface of the inner body, outlets are provided between the pitches of the screw blades, and the discharge direction of the mixture is in the spiral direction of the screw blades. It can be oriented along. According to this aspect, the mixture discharged from the discharge port flows along the screw blades and is therefore less susceptible to interference by the screw blades, and thus is less likely to slow down in the rotational direction.

In some embodiments, the region along the inner peripheral surface of the outer body is formed with a liquid layer in which the solid is separated from the mixture, and the outlet is outside the interface between the liquid layer and the gas region. The mode may be provided at a position away from the inner peripheral surface of the body portion. According to this aspect, the mixture is indirectly mixed into the liquid layer through the gas region, and it is difficult to directly affect the solid-liquid separability in the liquid layer.

In some embodiments, the region along the inner peripheral surface of the outer body may be formed with a liquid layer in which the solid is separated from the mixture, and the outlet may be arranged within the liquid layer. it can. According to this aspect, the mixture is released directly in the liquid layer toward the front in the direction of rotation. As a result, the speed difference in the rotation direction that occurs with the liquid layer becomes small.

According to some aspects of the present disclosure, it is advantageous to stably maintain the liquid layer separated from the solid, and the solid-liquid separability is not impaired.

FIG. 1 is a perspective view showing a screw decanter type centrifuge according to the embodiment. FIG. 2 is a vertical cross-sectional view showing the internal structure of the outer body bowl and the inner body screw conveyor according to the embodiment. FIG. 3 is a schematic cross-sectional view taken along the line III-III of FIG. FIG. 4 is an enlarged side view showing a part of the inner body screw conveyor. FIG. 5 is a cross-sectional view of an inner body screw conveyor corresponding to FIG. 3 and according to another embodiment. FIG. 6 shows a centrifuge device according to the first embodiment, and FIG. 6A is an explanatory view showing a swirl state when the inside of the outer body bowl and the inner body screw conveyor is viewed from the direction of the rotation axis. FIG. (B) is an explanatory diagram showing a state of liquid flow in the liquid layer. FIG. 7 shows a centrifuge device according to Comparative Example 1, FIG. 7A is a vertical sectional view showing an internal structure of a part of an outer body bowl and an inner body screw conveyor, and FIG. 7B is an outer view. It is explanatory drawing which shows the state of the swirl when the inside of the body bowl and the inner body screw conveyor is seen from the direction of the rotation axis, and (c) figure is the explanatory view which shows the state of the flow of liquid in a liquid layer. FIG. 8 is a graph showing the solid particle recovery rate (separation efficiency) in Example 2 and Comparative Examples 2 and 3.

Hereinafter, embodiments of the centrifuge device will be described in detail with reference to the drawings. In the description of the drawings, the same elements or the corresponding elements may be designated by the same reference numerals, and duplicate description may be omitted.

Centrifugal separation treatment is used as a solid-liquid separation treatment for separating a mixture of a solid which is a heavy component and a liquid which is a light component (hereinafter referred to as "stock solution"). In the centrifugation treatment, for example, the stock solution is rotated at high speed in the rotating body, and the sedimentation speed of the solid is increased by the centrifugal force in the radial direction applied to the rotating body to promote solid-liquid separation. In the present embodiment, as an apparatus for realizing this centrifugation treatment, a screw decanter type centrifugation apparatus will be described as an example.

As shown in FIGS. 1 and 2, the centrifugal separator 1 has a rotating body 2 which is a main part for realizing a centrifugal separation process, a casing 5 for accommodating the rotating body 2, and a desired rotational force on the rotating body 2. The drive unit 6 is provided, and the feed pipe 7 for supplying the undiluted solution M into the rotating body 2 is provided. The centrifuge 1 is used in various fields such as manufacturing processes for foods, drinking water, chemicals, chemical products, steel products, etc., and water treatments such as urine treatment, sewage treatment, slurry treatment, and factory wastewater treatment. Used for separation. It can also be used for solid-liquid separation of treated products such as bacterial cells and microorganisms that do not want to give an impact to a solid as much as possible.

The rotating body 2 includes an outer body bowl 3 (outer body portion) and an inner body screw conveyor 4 arranged in the outer body bowl 3. The rotation direction Ra of the outer body bowl 3 (see FIG. 3) and the rotation direction Ra of the inner body screw conveyor 4 are the same. The outer body bowl 3 is a cylindrical body having a substantially cylindrical shape, and the shaft portions at both ends are rotatably supported by bearings 3a. The main part of the outer body bowl 3 is arranged in the casing 5. The rotation axis L of the outer body bowl 3 extends in the longitudinal direction of the outer body bowl 3 so as to pass through both bearings 3a. The outer body bowl 3 houses the undiluted solution M inside, rotates by the action of the drive unit 6, and centrifuges the liquid Lq and the solid Sd (see FIG. 3) from the undiluted solution M.

As shown in FIG. 2, one end side of the outer body bowl 3 in the direction of the rotation axis (direction along the rotation axis L) is gradually reduced in diameter, and the throttle portion 31 is formed by this diameter reduction. There is. The throttle portion 31 is provided with a solid discharge port 32 for discharging the solid Sd conveyed by the inner body screw conveyor 4. A small diameter side outer body shaft 33 that seals (closes) the outer body bowl 3 is fixed to one end of the outer body bowl 3. The small diameter side outer body shaft 33 is rotatably supported by an external bearing 3a (see FIG. 1). A feed pipe 7 is arranged at the center of the small diameter side outer body shaft 33 so as to penetrate the small diameter side outer body shaft 33. The feed pipe 7 extends along the rotation axis L of the outer body bowl 3 and is supported by the feed pipe holder 7a. The undiluted solution M supplied into the outer body bowl 3 passes through the feed pipe 7. The inner body screw conveyor 4 is arranged so as to surround a part of the feed pipe 7. The small diameter side outer body shaft 33 of the inner body screw conveyor 4 and the outer body bowl 3 is rotatably connected via a bearing 34.

A large-diameter outer body shaft 35 is provided at the other end of the outer body bowl 3 in the direction of the rotation axis. The large-diameter outer body shaft 35 includes an annular inner wall portion 35a that seals (closes) the space between the outer body bowl 3 and the inner body screw conveyor 4, and the outer body bowl 3 from the central portion of the inner wall portion 35a. An inner shaft portion 35b protruding inward and an outer shaft portion 35c protruding outward from the outer body bowl 3 from the central portion of the inner wall portion 35a are provided. A bearing 35d that pivotally supports the inner body screw conveyor 4 is attached to the inner shaft portion 35b. The outer shaft portion 35c is rotatably supported by an external bearing 3a (see FIG. 1). A plurality of liquid passage ports 36 through which the liquid Lq separated from the solid Sd in the liquid layer passes and is discharged are provided at the position of the inner wall portion 35a on the outer side of the centrifugal CD. The plurality of liquid passage ports 36 are provided along the inner peripheral surface 3b of the outer body bowl 3.

The inner body screw conveyor 4 includes an inner body portion 41 which is a substantially cylindrical tubular body, and screw blades 42 which are provided on the outer peripheral surface 41a of the inner body portion 41 and project outward in the radial direction. The inner body portion 41 rotates in the same direction as the rotation direction Ra of the outer body bowl 3. The screw blade 42 is spirally wound around the outer peripheral surface 41a of the inner body portion 41. The screw blade 42 rotates with the rotation of the inner body portion 41, and transfers the solid Sd centrifuged from the liquid Lq to one end side of the inner body portion 41. One end side of the inner body portion 41 is reduced in diameter so as to correspond to the reduced diameter of the outer body bowl 3. One end of the inner body 41 is rotatably connected to the feed pipe 7 and the outer body bowl 3 via a bearing 34.

The peripheral wall 43 of the inner body portion 41 is provided with a passage port 8 through which the stock solution M passes, and a stock solution guide portion 9 that interferes with the stock solution M that has passed through the passage port 8 and changes the discharge direction of the stock solution M. The stock solution guide portion 9 is formed with a discharge port 91 for discharging the stock solution M between the inner peripheral surface 3b of the outer body bowl 3 and the inner body portion 41, and a stock solution flow path 92. The undiluted solution flow path 92 is curved from the passage port 8 and is connected to the discharge port 91, and connects the passage port 8 and the discharge port 91.

The undiluted solution guide portion 9 may be welded to the outer peripheral surface 41a of the inner body portion 41, or may be integrally formed with the inner body portion 41. Further, since the undiluted solution guide portion 9 may be worn by the fixed particles in the undiluted solution M, the undiluted solution guide portion 9 can be made into a structure (for example, a bush) that can be replaced with respect to the inner body portion 41. Is.

The undiluted solution M to be centrifuged is supplied to the inside of the inner body portion 41 through the feed pipe 7, and then passes through the passage port 8 and the undiluted solution flow path 92 of the inner body portion 41 to the discharge port 91. Is released from. The undiluted solution M supplied into the outer body bowl 3 from the discharge port 91 is centrifuged into the liquid Lq and the solid Sd by the rotation of the outer body bowl 3. The liquid Lq from which the solid Sd is separated forms a liquid layer LL that rotates following the inner peripheral surface 3b of the outer body bowl 3. More specifically, in the stock solution M, the solid Sd (mainly solid particles), which is a heavy component, is accumulated so as to be deposited on the inner peripheral surface 3b of the outer body bowl 3, and the liquid Lq, which is a light component, is accumulated. The liquid layer LL is formed so as to be mainly present inward of the solid Sd (in the direction opposite to the centrifugal direction CD). The surface layer surface of the liquid layer LL, that is, the surface formed inside the liquid layer LL is the boundary surface Bs between the gas region As where the solid Sd and the liquid Lq are sparse and the liquid layer LL.

The inner body screw conveyor 4 is settled in the centrifugal direction CD in the liquid layer LL, and the solid Sd deposited on the inner peripheral surface 3b of the outer body bowl 3 is brought to one end side of the outer body bowl 3 by the screw blades 42. send. A throttle portion 31 is provided on one end side thereof, and the solid Sd is dehydrated by the interaction between the throttle portion 31 and the screw blade 42, and is discharged from the solid discharge port 32.

An inner wall portion 35a is provided at the other end of the outer body bowl 3, and a liquid passage port 36 is provided at the inner wall portion 35a. The liquid Lq forming the liquid layer LL passes through the liquid passage port 36 of the inner wall portion 35a and is discharged to the outside. At least a part of the liquid passage port 36 is blocked by the orifice plate 37. More specifically, the orifice plate 37 is closed so as to block a part of the entire region of the liquid passage port 36 on the side closer to the inner peripheral surface 3b of the outer body bowl 3. As a result, the thickness of the liquid layer LL, in other words, the height from the inner peripheral surface 3b of the outer body bowl 3 to the boundary surface Bs of the liquid layer LL is defined by the height of the orifice plate 37. The height of the orifice plate 37 is substantially from the position closest to the inner peripheral surface 3b of the outer body bowl 3 to the inner peripheral surface 3b in a part of the liquid passage port 36 blocked by the orifice plate 37. Means the distance of.

The drive unit 6 includes a drive motor 61 that rotates the outer body bowl 3 in one direction and imparts a centrifugal separation function to the outer body bowl 3. The outer body bowl 3 is rotated at a high speed of, for example, 10 rpm to 10000 rpm by the drive motor 61. Further, the drive unit 6 includes a differential speed braker 62 for rotating the inner body screw conveyor 4, a planetary gear mechanism of the gearbox 63, and the like. The inner body portion 41 of the inner body screw conveyor 4 rotates at high speed in the same direction as the outer body bowl 3 by the power of the differential speed brake 62 and the planetary gear mechanism of the gearbox 63. The difference in rotational speed between the inner body portion 41 and the outer body bowl 3 is 50 rpm or less. This rotation speed difference can be 15 rpm or less, 10 rpm or less, and 5 rpm or less.

Next, the orientations of the stock solution guide portion 9 and the discharge port 91 will be described with reference to FIGS. 2, 3, and 4. The undiluted solution guide portion 9 is a tubular body having a substantially semicircular cross section, and is provided so as to be laterally oriented along the tangential direction of the outer peripheral surface 41a of the inner body portion 41. One end of the stock solution guide portion 9 is curved and closed, and a discharge port 91 is provided at the other end. The internal space of the undiluted solution guide portion 9 that serves as the undiluted solution flow path 92 communicates with the passage port 8 of the inner body portion 41 on one end side and communicates with the discharge port 91 on the other end side.

The discharge port 91 is arranged so as to face the front in the rotation direction Ra of the inner body portion 41 with reference to the discharge direction Da of the stock solution M. In the present embodiment, the "rotation direction Ra of the inner body portion 41" means the rotation direction Ra of the inner body screw conveyor 4, and is the same direction as the rotation direction Ra of the outer body bowl 3. Further, even when the inner body screw conveyor 4 is in a stationary state, if the spiral shape of the screw blades 42 is observed, the solid Sd is placed on one end side (throttle part 31 side) of the outer body bowl 3. The rotation direction Ra to be sent can be specified. That is, the rotation direction Ra specified based on the spiral shape of the screw blade 42 is the rotation direction Ra of the inner body portion 41. Next, "with reference to the discharge direction Da of the stock solution M" means that the direction of the discharge port 91 is defined based on the discharge direction Da of the stock solution M discharged from the discharge port 91. As a result, the discharge direction Da of the undiluted solution M discharged through the substantially central portion of the discharge port 91 is substantially the direction of the discharge port 91. If a plane including the peripheral edge (for example, a circle) of the discharge port 91 can be assumed, the normal direction of this plane can be defined as the direction of the discharge port 91.

Further, "facing the front of the rotation direction Ra of the inner body portion 41" means that the discharge direction Da or the normal direction is substantially the front side of the rotation direction Ra. Further, when a reference plane Px passing through the rotation axis L and the center of the discharge port 91 is assumed and the region Qx on the normal rotation side and the region Qy on the reverse rotation side in the rotation direction Ra are distinguished with the reference plane Px in between. , "In front of the rotation direction Ra" means that the region Qx on the normal rotation side is widely included. Therefore, "facing the front of the rotation direction Ra of the inner body portion 41" means, for example, not only the normal direction of the reference plane Px toward the region Qx on the normal rotation side, but also tilted with respect to this normal direction. It may be a direction.

The stock solution guide portion 9 is provided at the pitch interval Pd of the screw blade 42, and the longitudinal direction of the stock solution guide portion 9 is arranged so as to be a direction along the spiral direction of the screw blade 42. Therefore, the discharge direction Da of the stock solution M according to the present embodiment is the direction along the spiral direction of the screw blade 42. The discharge direction Da of the undiluted solution M is not limited to the direction along the spiral direction of the screw blade 42, and widely includes a direction that is non-parallel to the rotation axis direction, for example, a direction orthogonal to the rotation axis direction. Is also good.

The top portion 9a of the stock solution guide portion 9 is located at the position farthest from the outer peripheral surface 41a of the inner body portion 41. In the present embodiment, the top portion 9a of the stock solution guide portion 9 is not buried in the liquid layer LL, and the discharge port 91 is separated from the boundary surface Bs of the liquid layer LL from the inner peripheral surface 3b of the outer body bowl 3. It is provided at the above position. Here, supplementing the boundary surface Bs of the liquid layer LL, the boundary surface Bs is defined by, for example, the position 36a of the peripheral edge of the liquid passage port 36 closest to the inner peripheral surface 3b of the outer body bowl 3. The distance d2 from the boundary surface Bs defined with reference to this position 36a to the inner peripheral surface 3b of the outer body bowl 3 is the distance from the top 9a of the stock solution guide portion 9 to the inner peripheral surface 3b of the outer body bowl 3. Shorter than d1.

Next, the operation and effect of the centrifuge device 1 according to the present embodiment will be described. In the centrifuge device 1, the undiluted solution M discharged from the discharge port 91 of the undiluted solution guide portion 9 toward the front in the rotation direction Ra moves toward the centrifugal direction CD while changing its trajectory and mixes with the liquid layer LL.

Here, for example, it is assumed that the stock solution guide portion 9 is not provided and the stock solution M is discharged from the passage port 8 toward the centrifugal CD (comparative form). In the comparative form, the undiluted solution M discharged from the passage port 8 of the inner body portion 41 has a rotation speed of vθb. The undiluted solution M reaches the boundary surface Bs of the liquid layer LL at a rotation speed of vθb while moving in the centrifugal direction CD. On the other hand, the liquid layer LL rotates following the rotation of the outer body bowl, and it can be assumed that the boundary surface Bs of the liquid layer LL has a rotation speed vθa corresponding to the rotation speed of the outer body bowl. As a result, the difference between the rotation speed vθa of the boundary surface Bs of the liquid layer LL and the rotation speed vθb of the undiluted solution M becomes large.

On the other hand, in the present embodiment, the stock solution M is discharged from the discharge port 91 toward the front side in the rotation direction Ra, so that the speed (rotation speed) in the rotation direction Ra can be easily increased. As a result, as compared with the comparative form, when the undiluted solution M is mixed in the liquid layer LL, the difference in rotation speed generated between the undiluted solution M and the liquid layer LL can be easily reduced.

Further, the stock solution guide portion 9 is provided between pitches Pd of the screw blades 42, and the discharge direction Da of the stock solution M is a direction along the spiral direction of the screw blades 42. As a result, the undiluted solution M discharged from the discharge port 91 flows along the screw blade 42 and is less likely to be interfered by the screw blade 42, so that the rotation speed is unlikely to decrease.

Further, the discharge port 91 is provided at a position farther from the inner peripheral surface 3b of the outer body bowl 3 than the boundary surface Bs, and the undiluted solution M discharged from the discharge port 91 is indirectly passed through the gas region As. Will be mixed into the liquid layer LL. As a result, the undiluted solution M discharged from the discharge port 91 is less likely to directly affect the solid-liquid separability in the liquid layer LL. As a result, in the liquid layer LL, there is a possibility that solid particles that are settling in the centrifugal direction CD and solid Sd that has already settled and deposited can be reduced, and a decrease in solid-liquid separability can be suppressed. There is.

Further, for example, when the processed product such as bacterial cells or microorganisms that does not want to give an impact to the solid Sd as much as possible is the undiluted solution M, according to the centrifuge device 1 according to the present embodiment, the undiluted solution M and the liquid layer LL are rotated. Since the difference in speed can be reduced, the impact applied to the solid Sd can be softened, which is advantageous.

Further, in the centrifugal separator 1 according to the present embodiment, the difference in rotational speed between the stock solution M and the liquid layer LL can be reduced without reducing the rotational speed of the outer body bowl 3, so that the centrifugal force required for solid-liquid separation can be reduced. Is likely to be maintained or increased.

On the other hand, as shown in FIG. 5, as another embodiment, the discharge port 91 may be arranged in the liquid layer LL. The centrifuge device 1A according to another embodiment has the same structure and elements as the centrifuge device 1 according to the above-described embodiment, and the same structures and elements are designated by the same reference numerals for detailed description. It will be omitted and the differences will be mainly explained.

The centrifuge device 1A includes a stock solution guide portion 9A erected in the centrifugal direction CD from the outer peripheral surface 41a of the inner body portion 41 toward the inner peripheral surface 3b of the outer body bowl 3. The stock solution guide portion 9A is provided with a discharge port 91 and a stock solution flow path 92, and the stock solution flow path 92 is connected to a passage port 8 and a discharge port 91 of the inner body portion 41. The discharge port 91 is arranged in the liquid layer LL. Further, the discharge port 91 is arranged so as to face the front in the rotation direction Ra of the inner body portion 41 with reference to the discharge direction Da of the stock solution M.

According to the centrifuge device 1A according to the present embodiment, the stock solution M is discharged toward the front in the rotation direction Ra through the discharge port 91. Therefore, the rotational speed is substantially increased as compared with the mode in which the CD is discharged in the centrifugal direction. As a result, it becomes easy to reduce the speed difference in the rotation direction Ra when the mixture is mixed in the liquid layer LL. In particular, in the present embodiment, the discharge port 91 is arranged in the liquid layer LL, and the undiluted solution M is directly discharged in the liquid layer LL toward the front in the rotation direction Ra. As a result, the velocity difference with respect to the liquid layer LL in the rotation direction Ra becomes small.

The centrifugal separators 1 and 1A according to the present disclosure have been described above based on the embodiment and other embodiments. However, the present disclosure is not limited to the above-described embodiments and the like. For example, in the above embodiment, the stock solution guide portions 9 and 9A in which the direction and height of the discharge port 91 are unchanged have been described as an example, but the direction and height of the discharge port 91 can be adjusted (for example, can be expanded and contracted). ) Can be used.

Hereinafter, the present disclosure will be described in more detail by way of examples, but the present disclosure is not limited to these examples. Further, with respect to Examples and Comparative Examples described later, the same elements and corresponding structures as those in the above-described embodiment may be designated by the same reference numerals as those in the above-described embodiment and the description thereof may be omitted.

(Example 1, Comparative Example 1)
The first embodiment (see FIG. 6) has a structure corresponding to the above-described embodiment, and the inner body portion 41 of the inner body screw conveyor 4 is equally spaced in the circumferential direction when viewed from the rotation axis direction. A plurality (four) passage ports 8, a stock solution guide portion 9, and a discharge port 91 are provided so as to be. The inner diameters of the passage port 8 and the discharge port 91 are 100 mm. The undiluted solution M is discharged through the discharge port 91 at a flow rate of ^{3 m 3 / h.} The difference in rotational speed between the outer body bowl 3 and the inner body portion 41 of the inner body screw conveyor 4 was set to 10 rpm.

Comparative Example 1 (see FIG. 7) is substantially the same as Example 1 except that the stock solution guide portion 9 provided with the discharge port 91 is not provided.

FIG. 6B is a diagram showing a swirl state when the insides of the outer body bowl 3 and the inner body portion 41 according to the first embodiment are viewed from the direction of the rotation axis, and FIG. 6B is a diagram showing a swirl state. a) It is a figure which shows typically the direction and the size of the flow in the liquid layer LL with respect to the outer body bowl 3 in the liquid layer LL of the region X of the figure. In addition, in the figure (b), the arrow extending to the left side with respect to the region X means that the flow is relatively back with respect to the speed of the rotation direction Ra of the outer body bowl 3, and the length of the arrow is It means the magnitude of backflow.

FIG. 7A is an enlarged cross-sectional view of a part of the outer body bowl 3 and the inner body portion 41 according to Comparative Example 1, and FIG. 7B is an enlarged cross-sectional view of the outer body bowl 3 and the inner body portion 41. It is explanatory drawing which shows the state of the swirl when the inside is seen from the direction of the rotation axis, and (c) figure is in the liquid layer LL of the region Y of FIG. It is a figure which showed the direction and the magnitude of a relative flow schematically. In addition, in the figure (b), the arrow extending to the left side with respect to the region Y means that the flow is relatively back with respect to the speed of the rotation direction Ra of the outer body bowl 3, and the length of the arrow is It means the magnitude of backflow.

As shown in FIG. 6A, in the first embodiment, the undiluted solution M discharged from the discharge port 91 of the undiluted solution guide portion 9 changes its trajectory toward the centrifugal CD so as to be curved, and is a liquid. It is mixed so as to be substantially orthogonal to the boundary surface Bs of the layer LL. Here, as shown in FIG. 6B, in the first embodiment, the rotation speed of the liquid layer LL near the boundary surface Bs flows backward relative to the rotation speed of the outer body bowl 3. However, the direction of flow and the like are relatively stable, which is effective for stably maintaining the liquid layer LL.

On the other hand, as shown in FIG. 7B, in Comparative Example 1, the undiluted solution M that passed through the passage port 8 of the inner body portion 41 was obliquely mixed with the boundary surface Bs of the liquid layer LL. ing. Here, as shown in FIG. 7 (c), the direction of the flow near the boundary surface Bs of the liquid layer LL of Comparative Example 1 is more turbulent than that of Example 1 (see FIG. 6 (b)). Is big. Further, the rotation speed of the liquid layer LL of Comparative Example 1 near the boundary surface Bs flows backward relative to the rotation speed of the outer body bowl 3. The magnitude of this backflow is larger than that of Example 1, and there is a possibility that the solid-liquid separability is adversely affected.

(Example 2, Comparative Example 2, Comparative Example 3)
FIG. 8 is a graph showing the solid particle recovery rate (separation efficiency). The second embodiment is an apparatus in which a stock solution guide portion 9 having a height of 40 mm is provided on an inner body portion 41 having an inner diameter of 100 mm, and the discharge port 91 is arranged toward the front in the rotation direction Ra. Comparative Example 2 is an apparatus substantially common to Example 2 except that the undiluted solution guide unit 9 is not provided. Comparative Example 3 is a device in which the discharge port 91 is arranged toward the rear (reverse side) of the rotation direction Ra.

As shown in FIG. 8, in Example 2, the solid particle recovery rate is improved as compared with Comparative Example 2 and Comparative Example 3.

1, 1A Centrifuge 3 Outer body bowl (outer body)
3b Inner peripheral surface 91 Discharge port 41 Inner body 42 Screw blade Bs Boundary surface As Gas region CD Centrifugal direction Da Discharge direction Ra Rotational direction LL Liquid layer Sd Solid Lq Liquid Pd Pitch M undiluted solution (mixture)
L rotation axis

Claims (4)

A tubular outer body that accommodates a mixture of solid and liquid and centrifuges the solid and liquid from the mixture by rotation.
An inner body portion that is arranged inside the outer body portion along the rotation axis of the outer body portion, transfers the mixture, and rotates in the same direction as the rotation direction of the outer body portion.
A screw blade provided on the outer peripheral surface of the inner body portion and for transferring the solid to one side of the inner body portion along the rotation axis is provided.
The inner body portion comprises a discharge port for discharging the mixture inside between the inner peripheral surface of the outer body portion and the inner body portion.
The centrifuge is arranged so that the discharge port faces forward in the rotation direction with respect to the discharge direction of the mixture. The screw blades are spirally provided on the outer peripheral surface of the inner body portion.
The outlet is provided between the pitches of the screw blades.
The centrifuge device according to claim 1, wherein the discharge direction of the mixture is a direction along the spiral direction of the screw blade. A liquid layer in which the solid is separated from the mixture is formed in a region of the outer body portion along the inner peripheral surface.
The centrifuge according to claim 1 or 2, wherein the discharge port is provided at a position away from the inner peripheral surface of the outer body portion with respect to the boundary surface between the liquid layer and the gas region. A liquid layer in which the solid is separated from the mixture is formed in a region of the outer body portion along the inner peripheral surface.
The centrifuge according to claim 1 or 2, wherein the discharge port is arranged in the liquid layer.