Classification device
The classification apparatus simplifies design and operation by using a divided casing structure and Coanda nozzle to control air flow, addressing the complexity and adjustment challenges of existing cyclone-type devices.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- YAMAMOTO IND
- Filing Date
- 2024-12-05
- Publication Date
- 2026-06-17
AI Technical Summary
The existing cyclone-type classification devices have a complex structure, making them difficult to design and operate, and require precise balancing of suction and air compressors to achieve effective particle size classification, which is challenging to achieve in practice.
A classification apparatus with a main casing divided into an upper, intermediate, and lower casing, featuring a frustoconical and cylindrical internal spaces, a slit for particle extraction, and a Coanda nozzle to promote swirling flows, allowing easy adjustment through air flow control.
The apparatus achieves easy design and operation with effective particle size classification by minimizing structural complexity and eliminating the need for complex power balancing, promoting efficient discharge of particles through controlled air flow.
Smart Images
Figure 2026098191000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a classification device for classifying and collecting solid particles.
Background Art
[0002] There is known a cyclone-type classification device that classifies and collects solid particles by utilizing the centrifugal force and fluid force acting on the solid particles in a swirling flow. For example, the classification device described in Patent Document 1 includes a substantially cylindrical cyclone cylinder, a first cylindrical collector disposed at the lower part of the cyclone cylinder, a second cylindrical collector disposed inside the first cylindrical collector, and an outflow pipe disposed inside the cyclone cylinder and communicating with the outside. The classification device described in Patent Document 1 further includes a suction blower connected to the outflow pipe for sucking out the air inside the cyclone cylinder, and an additional air flow introduction pipe and an air compressor for blowing air from the outside into the flow path formed in the gap between the first cylindrical collector and the second cylindrical collector.
[0003] According to the classification device described in Patent Document 1, a swirling flow is generated inside the cyclone cylinder. Among the solid particles to be processed, the solid particles with a small particle size stay at the center of the swirling flow and are thus discharged to the outside through the outflow pipe. The solid particles with a large particle size and the solid particles with an intermediate particle size move in a direction away from the center of the swirling flow, and thus flow into the flow path formed in the gap between the first cylindrical collector and the second cylindrical collector. The solid particles with an intermediate particle size that have flowed into the gap between the first cylindrical collector and the second cylindrical collector are blown back by the air ejected from the additional air flow introduction pipe and flow into the second cylindrical collector. As a result, the solid particles with a large particle size are discharged to the outside through the first cylindrical collector. The solid particles with an intermediate particle size are discharged to the outside through the second cylindrical collector.
[0004] Thus, according to the classification device described in Patent Document 1, the solid particles to be processed can be classified into three stages according to the size of the particle size.
Prior Art Documents
Patent Documents
[0005] [Patent Document 1] Patent No. 6533522 [Overview of the project] [Problems that the invention aims to solve]
[0006] The classification device described in Patent Document 1 has a complex structure, which makes it difficult to design. Furthermore, inside the cyclone cylinder of the classification device described in Patent Document 1, there is a mixture of upward flow drawn into the outlet pipe and downward flow toward the first and second cylindrical collectors. In the gap between the first and second cylindrical collectors, there is a mixture of large solid particles that are directed downward toward the gap and solid particles of intermediate size that are blown back toward the gap. Therefore, in order to obtain a good classification effect, it is necessary to balance the power of the suction blower and the air compressor so that the solid particles to be processed behave as desired. However, it is quite difficult to balance the power of the suction blower and the air compressor and obtain a good classification effect. In other words, the classification device described in Patent Document 1 has the problem of being difficult to adjust during operation.
[0007] This invention has been made in view of the above circumstances, and aims to provide a classification device that has a simple structure, is easy to design, and is easy to operate and adjust. [Means for solving the problem]
[0008] To achieve the above objective, the classification apparatus according to the present invention comprises a main casing having an upper casing, an intermediate casing located below the upper casing and connected to the upper casing, having a frustoconical internal space in which the cross-sectional area of the internal space gradually decreases as it goes downward, and a lower casing located below the intermediate casing and connected to the intermediate casing. Furthermore, the classification apparatus according to the present invention comprises a processing target inlet for introducing air containing solid particles to be processed into the upper casing, and a swirling flow excitation means for swirling the air inside the upper casing around the central axis of the upper casing. Moreover, the classification apparatus according to the present invention comprises an extraction slit located between the intermediate casing and the lower casing for extracting a portion of the air containing solid particles to be processed that has been introduced into the main casing, a first collector for collecting the air containing solid particles to be processed that has passed through the extraction slit, and a second collector for collecting the air containing solid particles to be processed that has passed through the lower casing.
[0009] The lower casing may have a frustoconical internal space, and the cross-sectional area of the internal space may gradually increase as it goes downwards.
[0010] The lower casing may have a cylindrical internal space.
[0011] A baffle plate may be provided at the uppermost end of the lower casing, protruding from the inner surface of the lower casing into the internal space of the lower casing.
[0012] The second collector is positioned inside the lower casing and is equipped with a Coanda nozzle into which air containing solid particles to be processed that have passed through the lower casing flows. The Coanda nozzle may also have a slit that flows along the outer surface of the Coanda nozzle and excites a swirling flow that flows in the direction of the longitudinal axis of the Coanda nozzle while swirling around the longitudinal axis of the Coanda nozzle. [Effects of the Invention]
[0013] The classification apparatus according to the present invention has a simple structure, making it easy to design and manufacture. Operation adjustment of the classification apparatus according to the present invention is also easy, as it only requires adjusting the flow rate or flow rate of the air containing the solid particles to be processed that flows into the classification apparatus. Thus, according to the present invention, a classification apparatus that is easy to design, manufacture, and operate can be obtained. [Brief explanation of the drawing]
[0014] [Figure 1] This is a longitudinal cross-sectional view of a classification apparatus according to an embodiment of the present invention. [Figure 2] (A) is a cross-sectional view of the classification apparatus shown in Figure 1, obtained by cutting it along the plane indicated by line AA' in Figure 1, and (B) is an enlarged view of the classification apparatus shown in Figure 1, obtained by expanding the area indicated by arc B in Figure 1. [Figure 3] Figure 1 is an explanatory diagram illustrating the configuration and operation of the Coanda nozzle in the classification apparatus shown, where (A) is a side view of the Coanda nozzle, (B) is a view of the Coanda nozzle from the direction indicated by arrow b in (A), and (C) is a view of the Coanda nozzle from the direction indicated by arrow c in (A). (D) is a cross-sectional view of the Coanda nozzle 9 obtained by cutting it through the plane indicated by line dd' in (A). [Figure 4] This is an explanatory diagram illustrating the effect of the Coanda nozzle, where (A) is a longitudinal cross-sectional view showing an enlarged portion of the classification apparatus described in Figure 1, and (B) is a longitudinal cross-sectional view showing the configuration shown in (A) with the Coanda nozzle removed. [Modes for carrying out the invention]
[0015] The configuration and operation of the classification apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings. In each drawing, the same or equivalent parts are denoted by the same reference numerals.
[0016] (Overall structure) Figure 1 is a longitudinal cross-sectional view of a classification apparatus 1 according to an embodiment of the present invention, taken by cutting the classification apparatus 1 through a plane containing the central axis X. Figure 2(A) is a transverse cross-sectional view of the classification apparatus 1 taken by cutting through the plane indicated by line AA' in Figure 1. Figure 2(B) is an enlarged view of the classification apparatus 1, showing an enlarged view of the area indicated by arc B in Figure 1. As shown in Figure 1, the classification apparatus 1 comprises a main casing 2, a first cylindrical collector 3, and a second cylindrical collector 4. Solid particles P to be processed are introduced into the main casing 2 along with air. Of the solid particles P introduced into the main casing 2, larger solid particles P1 are collected in the first cylindrical collector 3 through a process described later, and then discharged. Smaller solid particles P2 are collected in the second cylindrical collector 4 and then discharged. Thus, according to the classification device 1, the solid particles P to be processed are classified into solid particles P1 with a large particle size and solid particles P2 with a small particle size. The first cylindrical collector 3 and the second cylindrical collector 4 are examples of the first and second collectors in the present invention.
[0017] Air containing large solid particles P1 discharged from the first cylindrical collector 3 flows through a pipeline (not shown) to a filter (not shown). Air containing small solid particles P2 discharged from the second cylindrical collector 4 flows through a pipeline (not shown) to an agglutination device (not shown). The small solid particles P2 are agglutinated in the agglutination device, and their particle size is increased. Air containing the solid particles agglutinated in the agglutination device flows through a pipeline (not shown) to the filter. The solid particles are collected by the filter, and the air is released into the atmosphere.
[0018] Now, as shown in FIG. 1, the main casing 2 includes an upper casing 5, an intermediate casing 6 located below the upper casing 5 and connected to the upper casing 5, and a lower casing 7 disposed below the intermediate casing 6. The upper casing 5 has a cylindrical internal space, and the cross-sectional area of the internal space does not change in the vertical direction. The intermediate casing 6 has a frustum-shaped internal space, and the cross-sectional area of the internal space gradually decreases as it goes downward. The lower casing 7 has a frustum-shaped internal space, and the cross-sectional area of the internal space gradually increases as it goes downward. With such a configuration, the cross-sectional area of the internal space of the main casing 2 is minimized at the boundary between the intermediate casing 6 and the lower casing 7. Thus, the main casing 2 as a whole constitutes a Venturi tube.
[0019] As shown in FIG. 1, a slit 8 is formed between the intermediate casing 6 and the lower casing 7. And the slit 8 communicates with the first cylindrical collector 3. As will be described later, among the solid particles P to be processed, the large-sized solid particles P1 flow through the slit 8 together with the air and into the first cylindrical collector 3. The small-sized solid particles P2 flow into the lower casing 7 together with the air. Thus, the slit 8 functions as an extraction slit for extracting a part of the air containing the solid particles to be processed introduced into the main casing 2.
[0020] As shown in FIG. 1, a Coandă nozzle 9 is connected below the lower casing 7. The air containing the small-sized solid particles P2 that has flowed into the lower casing 7 flows into the second cylindrical collector 4 through the Coandă nozzle 9. Note that the configuration and operation of the Coandă nozzle 9 will be described later.
[0021] As shown in FIGS. 1 and 2(A), four injection nozzles 10 are arranged on the upper casing 5. The injection nozzle 10 is a nozzle for blowing the air containing the solid particles P to be processed into the main casing 2. Note that the air containing the solid particles P to be processed is accelerated by a blower (not shown) and flows into the injection nozzle 10 through a pipeline (not shown).
[0022] As shown in Fig. 2(A), the four injection nozzles 10 are arranged radially from the center of the cross-sectional shape of the upper casing 5 and are equally spaced on the circumference around the center. And the injection nozzles 10 are directed in the tangential direction of the contour of the cross-sectional shape of the internal space of the upper casing 5. Therefore, when air is injected from the injection nozzles 10, a clockwise swirling flow S1 is generated. Thus, the injection nozzles 10 function as swirling flow excitation means for generating the swirling flow S1 within the upper casing 5. Further, the inlet of the injection nozzle 10 corresponds to a processing target introduction port for introducing air containing the solid particles P to be processed into the upper casing 5.
[0023] As described above, since the cross-sectional area of the internal space of the intermediate casing 6 gradually decreases downward, when the air flowing into the upper casing 5 descends within the intermediate casing 6, the swirling speed of the swirling flow S1 increases. On the other hand, since the cross-sectional area of the internal space of the lower casing 7 gradually increases downward, when the air passing through the intermediate casing 6 descends within the lower casing 7, the swirling speed of the swirling flow S1 decreases. Therefore, the swirling speed of the swirling flow S1 becomes maximum at the boundary between the intermediate casing 6 and the lower casing 7.
[0024] As mentioned above, the air introduced into the main casing 2 contains the solid particles P to be treated, so the swirling flow S1 generated within the main casing 2 also contains the solid particles P. Centrifugal force acts on the solid particles P within the swirling flow S1. The solid particles P, subjected to centrifugal force, move away from the center of the swirling flow, but a fluid force acts on the solid particles P in a direction that opposes this centrifugal movement. In other words, air resistance acts on the solid particles P. Roughly speaking, the magnitude of the air resistance experienced by the solid particles P is proportional to the surface area of the solid particles P. The magnitude of the centrifugal force acting on the solid particles P is proportional to the mass of the solid particles P. Also, the surface area of the solid particles P is proportional to the square of the particle size, and the mass of the solid particles P is proportional to the cube of the particle size. Therefore, the air resistance acting on large solid particles P1 is small compared to the centrifugal force. The air resistance acting on small solid particles P1 is large compared to the centrifugal force. As a result, larger solid particles P1 move away from the center of the swirling flow S1, while smaller solid particles P2 remain near the center of the swirling flow S1.
[0025] Thus, larger solid particles P1 in the swirling flow S1 move away from the center of the swirling flow S1, and as shown in Figure 2(B), at the boundary between the intermediate casing 6 and the lower casing 7, the larger solid particles P1 flow into the slit 8 along with the air. As mentioned above, the larger solid particles P1 that flow into the slit 8 flow into the first cylindrical collector 3 (not shown in Figure 2(B)). On the other hand, smaller solid particles P2 remain near the center of the swirling flow S1 and flow into the lower casing 7 along with the air. As shown in Figure 2(B), a baffle plate 11 is formed at the upper end of the lower casing 7, that is, below the entrance to the slit 8, protruding from the inner surface of the lower casing 7 toward the internal space of the lower casing 7. The baffle plate 11 obstructs the flow from the intermediate casing 6 toward the lower casing 7, so the flow from the intermediate casing 6 toward the lower casing 7 temporarily stagnates at the entrance to the slit 8. Therefore, it is prevented from some of the larger solid particles P1 passing past the entrance of the slit 8 and flowing down into the lower casing 7.
[0026] (Coanda nozzle configuration and operation) Figure 3 is an explanatory diagram illustrating the configuration and operation of the Coanda nozzle 9. Figure 3(A) is a side view of the Coanda nozzle 9, Figure 3(B) is a view of the Coanda nozzle 9 from the direction indicated by arrow b in Figure 3(A), and Figure 3(C) is a view of the Coanda nozzle 9 from the direction indicated by arrow c in Figure 3(A). Figure 3(D) is a cross-sectional view of the Coanda nozzle 9 taken by cutting it along the plane indicated by line dd' in Figure 3(A).
[0027] As shown in Figures 3(A) to 3(C), the Coanda nozzle 9 consists of an annular flange 9a and five rectifier plates 9b fixed to the flange 9a. As shown in Figure 3(D), the rectifier plates 9b have a crescent-shaped cross-section and are arranged so that the overall cross-sectional shape of the Coanda nozzle 9 is annular. The five rectifier plates 9b are arranged with small gaps between them in the cross-sectional shape of the Coanda nozzle 9, and slits 9c are formed between adjacent rectifier plates 9b. Also, as shown in Figure 3(A), the slits 9c are formed along the entire length of the Coanda nozzle 9, that is, from the base in contact with the flange 9a to the tip of the Coanda nozzle 9.
[0028] Furthermore, as shown in Figure 3(D), the inlet of the slit 9c on the inside of the Coanda nozzle 9 is tangent to the inner circumference of the cross-sectional shape of the Coanda nozzle 9, and is oriented to receive the swirling flow flowing from the lower casing 7 into the Coanda nozzle 9. The outlet of the slit 9c on the outside of the Coanda nozzle 9 is tangent to the outer circumference of the cross-sectional shape of the Coanda nozzle 9.
[0029] Since the slit 9c is formed as described above, some of the air flowing from the lower casing 7 into the Coanda nozzle 9 flows into the slit 9c, passes through the slit 9c, and exits the Coanda nozzle 9. At this time, the air that has passed through the slit 9c is ejected in the direction indicated by the arrow in Figure 3(D). The airflow ejected from the slit 9c is bent by the Coanda effect in a direction along the outer circumference of the Coanda nozzle 9, and swirls along the outer circumference of the Coanda nozzle 9. Since the airflow flowing into the Coanda nozzle 9 originally has a downward velocity vector, the air that has passed through the slit 9c flows toward the tip of the Coanda nozzle 9 while circling along the outer circumference of the Coanda nozzle 9. As a result, as shown in Figure 3(A), a spiral swirling flow S2 is excited that swirls along the outer circumference of the Coanda nozzle 9 toward the tip of the Coanda nozzle 9. The swirling flow S2 continues to flow beyond the tip of the Coanda nozzle 9 and below the Coanda nozzle 9, and is maintained as it flows along the inner surface of the second cylindrical collector 4. In this way, the swirling flow S2 is maintained throughout the entire area of the second cylindrical collector 4. Furthermore, the small solid particles P2 discharged from the lower end of the Coanda nozzle 9 flow downward through the swirling flow S2.
[0030] Thus, a Coanda nozzle 9 is positioned inside the second cylindrical collector 4, and a swirling flow S2 is excited by the Coanda nozzle 9. The small solid particles P2 discharged from the lower end of the lower casing 7 are carried away by the swirling flow S2, or guided by the swirling flow S2, and flow away to the bottom of the second cylindrical collector 4. As a result, random movement of the small solid particles P2 inside the second cylindrical collector 4 is suppressed. Alternatively, retention of the small solid particles P2 inside the second cylindrical collector 4 is suppressed. In other words, the discharge of small solid particles P2 from the second cylindrical collector 4 is promoted.
[0031] (Effect of Coanda nozzle) Figure 4(A) is a longitudinal cross-sectional view showing an enlarged portion of the classification apparatus 1 described in Figure 1, and Figure 4(B) is a longitudinal cross-sectional view showing the configuration shown in Figure 4(A) with the Coanda nozzle 9 removed. In the following, the effect of the Coanda nozzle 9 will be explained by comparing the airflow inside the second cylindrical collector 4 with and without the Coanda nozzle 9, referring to Figures 4(A) and 4(B).
[0032] As shown in Figure 4(A), when the second cylindrical collector 4 is equipped with a Coanda nozzle 9, the airflow 12 discharged from the Coanda nozzle 9 flows downwards towards the second cylindrical collector 4 without diffusion and with almost no deceleration. Therefore, as described above, solid particles contained in the airflow 12 are quickly discharged from the second cylindrical collector 4.
[0033] On the other hand, if the second cylindrical collector 4 is not equipped with a Coanda nozzle 9, as shown in Figure 4(B), the airflow 13 discharged from the lower casing 7 diffuses into the second cylindrical collector 4, reducing its flow velocity. Also, a vortex 14 is generated inside the second cylindrical collector 4. As a result, the discharge rate of solid particles contained in the airflow 13 from the second cylindrical collector 4 decreases. Furthermore, some of the solid particles remain inside the second cylindrical collector 4.
[0034] As explained above, the classifier 1 has a simple structure and no mechanical moving parts, making it easy to manufacture. Furthermore, in operating the classifier 1, it is sufficient to control the flow rate or velocity of the air containing the solid particles P to be processed, and there are no other controls to be made. Therefore, operational adjustments are easy. In addition, since the swirling flow S2 excited by the Coanda nozzle 9 promotes the discharge of solid particles P2, there is no need to provide a device to promote the discharge of solid particles P2, such as a blower, outside the classifier 1.
[0035] However, the technical scope of the present invention is not limited by the embodiments described above. The present invention can be freely modified, applied, or improved upon to the extent of the technical idea described in the claims. Needless to say, components not mentioned in the description of the embodiments above can be added.
[0036] In particular, the shapes of the internal spaces of the upper casing 5 and the lower casing 7 are not limited by the above description. In the present invention, it is sufficient that the slit 8 is formed in the main casing 2 at the location where the cross-sectional area is minimized. As long as this condition is satisfied, the shapes of the upper casing 5 and the lower casing 7 can be arbitrarily changed. The upper casing 5 may have a frustoconical internal space in which the cross-sectional area of the internal space gradually decreases from top to bottom. The lower casing 7 may have a cylindrical internal space. In other words, the flow path cross-sectional area of the internal space of the lower casing 7 may be constant in the vertical direction.
[0037] Furthermore, although the main casing 2 was divided into an upper casing 5, an intermediate casing 6, and a lower casing 7 in the above description, this division is based on function. The main casing 2 is not limited to being composed of three physically independent parts. The upper casing 5, the intermediate casing 6, and the lower casing 7 may be physically or mechanically integrated. In other words, the main casing 2 may be machined from a single material or molded as a single piece.
[0038] In the above example, an example with four injection nozzles 10 was shown, but the number of injection nozzles 10 is not limited to four. There may be one injection nozzle 10, two, three, or five or more. In fact, the swirling flow excitation means provided in the main casing 2 is not limited to injection nozzles 10. Various known swirling flow excitation means can be arbitrarily selected. The swirling flow excitation means may be, for example, guide vanes arranged in the internal space of the main casing. [Industrial applicability]
[0039] The classification apparatus according to the present invention is useful in industrial or consumer fields as a classification apparatus for classifying solid particles to be processed according to their particle size. [Explanation of Symbols]
[0040] 1 Classification device, 2 Main casing, 3 First cylindrical collector, 4 Second cylindrical collector, 5 Upper casing, 6 Intermediate casing, 7 Lower casing, 8 Slit, 9 Coanda nozzle, 9a Flange, 9b Rectifier plate, 9c Slit, 10 Injection nozzle, 11 Baffle plate, 12,13 Airflow, 14 Vortex, P Solid particles to be processed, P1 Large solid particles, P2 Small solid particles, S1,S2 Swirling flow
Claims
1. A main casing comprising an upper casing, an intermediate casing located below the upper casing and connected to the upper casing, having a frustoconical internal space in which the cross-sectional area of the internal space gradually decreases as it goes downward, and a lower casing positioned below the intermediate casing and connected to the intermediate casing, The upper casing has a processing port for introducing air containing solid particles to be processed, The upper casing is equipped with a swirling flow excitation means that causes the air inside the upper casing to swirl around the central axis of the upper casing, An extraction slit is located between the intermediate casing and the lower casing, for extracting a portion of the air containing the solid particles to be processed that has been introduced into the main casing, A first collector for collecting air containing solid particles to be processed that has passed through the extraction slit, The system includes a second collector for collecting air containing solid particles to be processed that have passed through the lower casing, Classifying device.
2. The lower casing has a frustoconical internal space, and the cross-sectional area of the internal space gradually increases as it goes downwards. The classification apparatus according to claim 1.
3. The lower casing has a cylindrical internal space. The classification apparatus according to claim 1.
4. The lower casing is provided with a baffle plate located at the uppermost end of the lower casing, which protrudes from the inner surface of the lower casing into the internal space of the lower casing. The classification apparatus according to claim 1.
5. The second collector is positioned inside the lower casing and is equipped with a Coanda nozzle into which air containing solid particles to be processed that have passed through the lower casing flows, The Coanda nozzle has a slit that excites a swirling flow that flows along the outer circumferential surface of the Coanda nozzle, swirls around the longitudinal axis of the Coanda nozzle, and flows in the direction of the longitudinal axis of the Coanda nozzle. A classification apparatus according to any one of claims 1 to 4.