JP6533522B2 - Cyclone-type powder classifier - Google Patents

Description

  The present invention relates to a cyclone-type powder classification device using centrifugal force.

  With regard to powder classification, with the development of ceramic industry and so on, with the advancement of technology, demands for improvement of classification performance, prevention of contamination during classification, large-scale treatment and the like are increasing.

  For example, a cyclone-type powder classification apparatus as shown in FIG. 20 is known as a cyclone-type powder classification apparatus for classifying powder distributed in a predetermined particle size range into coarse powder and fine powder (for example, a patent) Reference 1).

In such a cyclone type powder classification apparatus, an air flow containing dispersed powder in a dry state, for example, along the inner wall surface from the opening 2a of the inflow pipe 2 in the upper part of the substantially upright cylindrical cyclone cylinder 3 An air flow is blown in the horizontal direction to form a swirling flow R in the centrifugal separation chamber 4 in the cyclone cylinder 3, and coarse powder having a large volume of powder contained in the swirling flow R is converted to the swirling flow. Since it gradually settles down, it is collected by the collector 10 provided at the lower part of the cyclone cylinder 3, while fine powder with a small volume is discharged from the outflow pipe 8 disposed above the central portion of the swirling flow of the cyclone cylinder 3. It is configured to be extracted upward and recovered.

In such a cyclone-type powder classification apparatus, for example, powder having fine particles of less than 5 μm, intermediate particles of 5 to 30 μm, and coarse particles of 30 μm or more requires powder having a particle diameter of 5 to 30 μm. In this case, as a classification point, particles having a particle size of less than 5 μm are removed by extracting an air flow containing fine particles upward from the outflow pipe 8 (in the present specification, “particle size” means Volume equivalent diameter)
By the way, in recent years, more accurate classification may be required. For example, in the case of providing an optical functional layer on the surface of various displays represented by liquid crystal displays, the particles dispersed in the coating layer may be confirmed as unevenness or streak-like defects if they are not uniform. There is a need to incorporate uniform particles.

  In such a case, for example, 30 μm is again classified as a second classification point, and powder of coarse particles of 30 μm or more is removed.

JP 2011-125801 A

  In view of such circumstances, the present invention removes coarse particles from a coarse powder containing intermediate particles collected in a centrifugal separation chamber in a secondary classification chamber provided at a collection site to obtain desired particle sizes. An object of the present invention is to provide a cyclone-type powder classification device capable of separating powder.

In order to achieve the above object, a cyclone type powder classifying apparatus according to the present invention comprises a cylindrical upper peripheral wall 42 and a body leg 52 connected to a lower portion of the upper peripheral wall 42;
A first cylindrical collector 39 is provided at the lower portion of a substantially cylindrical cyclone cylinder 38 having a flared tapered portion 53 connected to the lower portion of the body leg 52,
In the centrifugal separation chamber 46 formed between the upper peripheral wall 42 and the body leg 52, powder having a particle size distribution is supplied through the inflow pipe 40,
A swirling flow R is formed in the centrifugal separation chamber 46 by sucking or discharging the air in the centrifugal separation chamber 46 through an outflow pipe 48 located above the centrifugal separation chamber 46 and communicating with the outside. And in a cyclone type powder classification device for separating the powder into fine powder and coarse powder by the swirling flow R,
The second cylindrical shape is disposed across the tapered portion 53 and the first cylindrical collector 39, the upper end portion is opened, and the fine particles separated from the opening portion of the lower end portion are passed through the passage 55a. It has a structure to take out from the collector 55, and has an inclined surface 55b at the top, which is disposed to face the inclined surface 53a of the tapered portion 53 so as to form a channel. A second cylindrical collector 55 whose upper portion is tapered, which forms an inclined passage 56 between the partition walls between the inclined surface 53a and the inclined surface 55b of the second cylindrical collector 55;
An additional air flow introduction pipe 57 connected to the side wall of the first cylindrical collector 39 or the side wall of the tapered portion 53 for introducing an additional air flow S into the centrifugal separation chamber 46;
The coarse powder guided downward with the swirling flow R in the centrifugal separation chamber 46 is guided from the lower end opening of the body leg 52 to the inclined passage 56 between the partition walls,
Intermediate particles m less than a predetermined weight contained in the coarse powder are moved from the outer peripheral side of the swirling flow R to the inner peripheral direction by the additional air flow S introduced into the centrifugal separation chamber 46 from the additional air flow introduction pipe 57 The intermediate particles m having the predetermined weight or less are thus guided inward by guiding the intermediate particles m having the predetermined weight or less through the upper end opening 55d of the second cylindrical collector 55. Configured to be separated from the lower end opening 55 c of the two cylindrical collectors 55 ,
A straight line in the vertical direction is extended from the inner peripheral wall of the lower end opening of the body leg (52) toward the inclined surface (55b) of the second cylindrical collector (55), and this straight line and the inclined surface Assuming that the position intersecting with (55b) is (E), the length extending from the position (E) to the outside of the inclined surface (55b) is (x) (where the straight line and the inclined surface (55b) If the length of the inclined surface (55b) is (x), the length of the inclined surface (53a) of the tapered portion (53) of the first cylindrical collector (39) Let (y) be
0.05 y ≦ x <y
It is characterized by being set to .

  According to the present invention having such a configuration, the tapered shape formed between the inclined surface 53a of the tapered portion 53 and the inclined surface 55b of the second cylindrical collector 55 whose upper portion is tapered. The flow of the additional air flow S can be generated in the inclined passage 56 between the partition walls, and the flow of the additional air flow S generated in the inclined passage 56 between the partition walls makes the space between the partition walls near the lower end opening of the body leg 52 Among the powder guided into the inclined passage 56, the intermediate particles m having a weight of a predetermined weight or less can be again lifted upward. In addition, when the powder is formed of a homogeneous material, the weight of the powder is proportional to the volume of the particle size, meaning that smaller particles mean lighter than large particles. .

  As described above, according to the present invention, the intermediate particle m is moved upward by causing the intermediate particle m having a small particle diameter (light weight) to rise upward again in the inclined passage 56 between the partition walls. It can be guided to the upper end opening 55d side, dropped from the upper end opening 55d into the inside thereof, and recovered from the lower end opening 55c via the second cylindrical collector 55. Therefore, intermediate particles m (e.g., 5 [mu] m to 30 [mu] m) with the adjusted particle size can be separated.

  On the other hand, although large particles M having a particle diameter of 30 μm or more and a heavy weight are guided to the inclined passage 56 between the partition walls, the large particles M have an additional air flow S Even if a flow occurs, it can not soar. As a result, the coarse particles M having a large particle size (heavy weight) pass between the inclined surface 53a of the diverging tapered portion 53 and the inclined surface 55b of the second cylindrical collector 55 and move downward according to the inertial force. Fall into Thereby, the coarse particles M are guided to the lower end opening 39 a side of the first cylindrical collector 39.

  As described above, in the cyclone-type powder classification device according to the present invention, first, fine particles (for example, less than 5 μm) can be discharged from the outflow pipe 48 to the outside. Further, among coarse particles including intermediate particles guided downward while being swirled by the swirling flow R in the centrifugal separation chamber 46, coarse particles M (for example, 30 μm or more) are attached to the lower end of the first cylindrical collector 39 It can be guided and accumulated on the side of the opening 39a.

  As a result, only powder (for example, 5 μm to 30 μm) whose particle size has been adjusted can be finally accumulated through the lower end opening 55 c of the second cylindrical collector 55. Become.

In the present invention, a spiral guide blade 47 may be disposed inward of the cyclone cylinder 38 to form a swirl flow in the centrifugal separation chamber 46 by the guide blade 47.

  In this way, even if the outflow pipe is not provided, the swirl flow can be easily formed by providing the guide vanes.

  Moreover, in the present invention, it is preferable that a plurality of the additional air flow introduction pipes 57 be formed at predetermined intervals in the circumferential direction.

  As described above, if a plurality of additional air flow introduction pipes 57 are formed at predetermined intervals, the powder falling in the tapered inter-partition inclined passage is more stable over substantially the entire circumferential direction. Can make powder fly up.

  Here, in the cyclone type powder classifying device according to the present invention, the additional air flow introduction pipe 57 is preferably connected so as to have a flow directed inward from the outer peripheral portion of the swirling flow R.

  Further, in the present invention, the additional air flow introduction pipe 57 is connected in the tangential direction of the first collector 39 or the diverging tapered portion 53 so as to increase the swirling speed of the swirling flow R. Is preferred.

  With such a configuration, the additional air flow S can increase the swirling speed of the swirling flow R.

In the present invention, the outer periphery of the first cylindrical collector 39 to which the additional air flow introduction pipe 57 is connected or the outer periphery of any one of the tapered portions 53 to which the additional air flow introduction pipe 57 is connected , Additional air flow storage chamber 67,
After the additional air flow S is temporarily gathered in the additional air flow storage chamber 67, the inward direction of the cyclone cylinder 38 or the air flow discharge hole 68 formed in the additional air flow storage chamber is further added. It is preferable to be supplied inward of the first cylindrical collector 39.

  With such a configuration, the swirling speed of the swirling flow R can be increased by the additional air flow S introduced from the air flow discharge hole 68, so that the classification performance can be improved.

Further, in the present invention, the swirling direction of the swirling flow U from the bottom to the top formed by the additional air flow S introduced from the additional air flow introduction pipe 57 is formed in the centrifugal separation chamber 46, The introduction direction of the additional air flow S is set so as to be in the same direction as the swirling direction of the swirling flow R from the lower side, and at the lower outlet of the inclined passage 56 between partition walls,
It is preferable that the rotational speed of the rotational flow R can be set to be smaller than the rotational speed of the rotational flow U.

  With such a configuration, the swirling flow U accelerates the swirling flow R, whereby the classification accuracy can be improved.

  Furthermore, in the present invention, the inflow tube 40 communicates with the centrifugal separation chamber 46 through the opening 43 formed in the upper peripheral wall 42 of the centrifugal separation chamber 46 and is tangent to the centrifugal separation chamber 46 It is preferable that they are connected in a direction.

  With such a configuration, ambient air can be introduced into the centrifuge chamber to generate a strong swirling flow.

  In the present invention, it is preferable that a plurality of air intake holes 62a for introducing the outside air into the centrifugal separation chamber 46 be formed in the upper peripheral wall 42 or the body leg 52 of the centrifugal separation chamber 46.

  With such a configuration, the speed of the swirling flow in the centrifugal separation chamber 46 can be increased by the external air introduced from the air intake hole 62a, and as a result, the classification performance can be improved.

  Alternatively, in the present invention, the air intake nozzle 62 b for introducing the outside air into the peripheral wall 42 or the body leg 52 of the centrifugal separation chamber 46 flows the swirling flow R to the peripheral wall 42 or the body leg 52 of the centrifugal separation chamber 46. It is preferable to be connected tangentially in the direction along.

  With such a configuration, the speed of the swirling flow in the centrifugal separation chamber 46 can be increased by the external air introduced from the air intake nozzle 62b, and as a result, the particle classification performance can be improved. Preferably, one or more nozzles 62b are formed.

In the present invention, a straight line in the vertical direction is extended from the inner peripheral wall of the lower end opening of the body leg 52 toward the inclined surface 55b of the second cylindrical collector 55, and this straight line and the inclined surface Assuming that a position at which 55b intersects is E, a length extending from the position E to the outside of the inclined surface 55b is x (however, when the straight line and the inclined surface 55b do not intersect, the inclined surface 55b Assuming that the length is x) and the length of the inclined surface 53a of the tapered portion 53 of the first cylindrical collector 39 is y,
0.05 y ≦ x <y
It is preferable to set to.

  Thus, setting x and y can improve classification performance.

In the present invention, the ratio of the radius r ₂ of the upper end opening portion of the radius r ₁ of the lower end opening of the body leg 52 and the second cylindrical collector 55 (r ₂ / r ₁₎ is 0 <r It is preferable that ₂ / r ₁ ≦ 1.30.

By so doing, the air flow having a high swirling speed is guided to the inclined passage between the partition walls, and the centrifugal force acting on the particles becomes large, so it is possible to make the classification point D _p50 small.

The powder classification method of the present invention uses the above-mentioned apparatus,
The swirling direction of the swirling flow U from the bottom to the top formed by the additional gas flow S introduced from the additional gas flow introduction pipe 57 is formed in the centrifugal separation chamber 46, the swirling flow R from the top to the bottom To introduce the additional air flow S in the same direction as the turning direction of
It is characterized in that the rotational speed of the rotational flow R <the rotational speed of the rotational flow U.

  With such a method, the swirling flow U accelerates the swirling flow R, whereby the classification accuracy can be further improved.

According to the cyclone-type powder classification device according to the present invention, the difference in the magnitude of the centrifugal force applied to the particles generated by the swirling flow in the cyclone cylinder and the swirling flow in the upper portion flow from the outer peripheral side of the swirling flow inward. The second cylindrical collection in which intermediate particles are provided inside the collector from among the powder having particle size distribution accumulated on the lower side of the cyclone cylinder by combining the drag of the additional air flow and the centrifugal force. The coarse particles are introduced into the vessel and dropped into the first cylindrical collector to separate the coarse particles from the powder having a particle size distribution accumulated on the lower side of the cyclone cylinder .

Thereby, in the present invention, classification performance in the cyclone cylinder can be improved.

  Further, the cyclone type powder classifying device according to the present invention has an effect that it is excellent in maintainability because there are few driving parts of the device.

FIG. 1 is a schematic configuration view of a cyclone type powder classifying device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the cyclone cylinder shown in FIG. FIG. 3 is an enlarged sectional view of an essential part showing the vicinity of the inclined passage between the partition walls of the cyclone type powder classifying device shown in FIG. FIGS. 4 (a) and 4 (b) are cross-sectional views of essential parts in the case of providing an air intake hole or a nozzle in a ring-shaped member of a cyclone type powder classifying device according to another embodiment of the present invention. Fig.5 (a), (b) is a schematic sectional drawing of the ring-shaped member employ | adopted by embodiment shown to FIG. 4 (a), (b). FIG. 6 is a cross-sectional view of the vicinity of the inflow pipe of the cyclone type powder classifying device shown in FIG. FIG. 7 is a schematic view showing the positional relationship of the second cylindrical collector of the cyclone type powder classifying device shown in FIG. Fig. 8 shows the experimental results, Fig. 8 (a) shows the frequency distribution of the raw material, Fig. 8 (b) shows the frequency distribution classified by the experiment, and Fig. 8 (c) shows the cyclone type powder It is explanatory drawing which showed the material balance when the raw material obtained with the whole classification apparatus is set to 100. FIG. FIG. 9 is a schematic configuration view of a cyclone type powder classifying device according to still another embodiment of the present invention. FIG. 10 (a) shows the partition wall of the cyclone type powder classification device when the additional air flow introduction pipe is connected in the tangential direction of the first collector to increase the swirling speed of the swirling flow of the centrifugal separation chamber 10 (b) is a schematic top view of FIG. 10 (a). FIG. Fig. 11 (a) is a schematic cross-sectional view showing the vicinity of the inclined passage between the partition walls of the cyclone type powder classifying device when the additional air flow storage chamber is provided on the outer periphery of the first cylindrical collector; Fig. 11 is a schematic top view of Fig. 11 (a). FIG. 12: is a figure which shows the frequency distribution of the raw material Y used in Examples 2-22. FIG. 13 shows the experimental results, and is a view showing the relationship between the particle size which is the classification result and the partial separation efficiency. FIG. 14 shows the experimental results, and is a view showing the relationship between the particle size which is the classification result and the partial separation efficiency. FIG. 15 shows the experimental results, and shows the relationship between the particle size which is the classification result and the partial separation efficiency. FIG. 16 shows the experimental results, and is a view showing the relationship between the particle size which is the classification result and the partial separation efficiency. FIG. 17 shows an experimental result, and is a view showing the relationship between the flow rate of the additional air flow and the classification accuracy index. Figure 18 is a diagram showing the radius r ₂ of the upper end opening portion of the radius r ₁ of the lower end opening of the body legs second cylindrical collector. 19 shows the experimental results, the ratio of the radius r ₁ of the lower end opening of the body legs and the radius r ₂ of the upper end opening portion of the second cylindrical collector 55 (r ₂ / r ₁₎ It is a figure which shows the relationship between and the classification point. FIG. 20 is a schematic view showing the behavior of a conventional cyclone type powder classifying apparatus.

  Hereinafter, preferred embodiments of a cyclone type powder classifying device according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration view of a cyclone-type powder classifying device 30 according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of a cyclone cylinder 38 shown in FIG.

The cyclone-type powder classification device 30 has a cylindrical cyclone cylinder 38 whose apex is directed in the vertical direction.

The cylindrical cyclone tube 38 has an upper peripheral wall 42, a tapered body leg 52 connected to the lower portion of the upper peripheral wall 42, and an end-extending tapered portion 53 connected to the lower portion of the body leg 52. There is. A main part of a centrifugal separation chamber 46 surrounded by an upper peripheral wall 42 and the body leg 52 is formed at an upper portion in the cyclone cylinder 38.

  The body leg 52 is not limited to being tapered, and may be formed in a substantially straight barrel shape or a diverging end.

Furthermore, a first cylindrical collector 39 is provided below the cyclone cylinder 38.

  Moreover, between the taper part 53 and the 1st cylindrical collector 39, the 2nd cylindrical collector 55 which the upper part tapered and bent and was formed is accommodated. The first cylindrical collector 39 is formed with an open upper end and a lower end, and has a lower end opening 39a communicating with another container or the like at the lower end. Further, a valve 64 is provided above the lower end opening 39a. In addition, the second cylindrical collector 55 formed by bending has an upper end and a lower end opened, and has an upper end opening 55d and a lower end opening 55c, and these openings are S-shaped. Are connected by a channel 55a. Further, a valve 66 is provided above the lower end opening 55c of the S-shaped passage 55a.

  Hereinafter, the second cylindrical collector 55 formed by bending will be further described.

  The second cylindrical collector 55 constitutes the main part of the present invention, and is classified by the outflow pipe 48, and further intermediates the powder toward the secondary separation chamber provided at the lower part of the centrifugal separation chamber 46. Used to classify particles and coarse particles. In addition, in this embodiment, the second cylindrical collector 55 is disposed so as to be adjustable in the vertical direction.

  The mechanism for enabling the position adjustment of the second cylindrical collector 55 in the vertical direction is not particularly limited. For example, a cross shaft gear is used as the positional relationship of the gear shaft, and a bevel gear is used as the type of gear. The transmission mechanism by a gear can be used. In addition, as the positional relationship of the gear shaft, it is possible to use, as another type of gear such as a staggered shaft gear, a spiral bevel gear, a hypoid gear, a cylindrical worm gear or the like.

  The second cylindrical collector 55 has an inclined surface 55b disposed at an upper portion substantially parallel to the inclined surface 53a of the diverging tapered portion 53, and the inclined surface 53a of the diverging tapered portion 53 and the second Between the partition walls, an inclined passage 56 is formed between the cylindrical collector 55 and the inclined surface 55 b of the cylindrical collector 55.

  The bent second cylindrical collector 55 in the present embodiment is formed as described above. Further, since the second cylindrical collector 55 is movable in the vertical direction, it is possible to move the second cylindrical collector 55 upward to bring the inclined surface 53b closer to the inclined surface 53a. The passage width of the inclined passage 56 between the partition walls is narrowed. On the other hand, if the second cylindrical collector 55 is moved downward and the inclined surface 55b is arranged to be far from the inclined surface 53a, the passage width of the inclined passage 56 between the partition walls can be expanded. Thereby, the flow rate of the air flow which flows here can be adjusted. Further, the coarse particles can be accumulated more in the first cylindrical collector 39 by widening the width.

  On the other hand, in the cyclone type powder classification device of the present embodiment, an additional air flow introducing pipe 57 for introducing an additional air flow S into the centrifugal separation chamber 46 is connected to the side wall portion of the first cylindrical collector 39 . The additional air flow introduction pipe 57 can also be connected to the side wall of the tapered portion 53 that is wide. It is preferable that a plurality of the additional air flow introduction tubes 57 be formed at predetermined intervals in the circumferential direction.

  The additional air flow introduction pipe 57 is for introducing external air as the additional air flow S into the centrifugal separation chamber 46 via the air compressor 63 and the flow meter 65, and the additional air flow S introduced from the additional air flow introduction pipe 57. As a result, a new air flow is generated in the centrifugation chamber 46.

  It is preferable that the additional air flow S from such an additional air flow introduction pipe 57 is connected so as to flow inward from the outer peripheral side of the swirling flow R, as shown by a dotted line in FIG.

On the other hand, in the cyclone-type powder classification device 30 of the present embodiment, the outflow pipe 48 is disposed on the central axis of the centrifugal separation chamber 46. The outflow pipe 48 is extended downward to a position lower than the height of the inflow pipe 40 for supplying the powder into the centrifugal separation chamber 46, and the lower end of the outflow pipe 48 is opened into the cyclone cylinder 38 to be separated into the centrifugal separation chamber 46. , And the upper end of the outflow pipe 48 is extended outward of the upper portion of the cyclone cylinder 38 to form an exhaust port 50 of air and fine powder.

  In addition, a fine powder recovery unit 51 formed of a bag filter or the like is connected to the air of the outflow pipe 48 and the fine powder discharge port 50, and a suction blower 54 is further connected. The suction blower 54 sucks the air in the centrifugal separation chamber 46 through the fine powder recovery unit 51 and the fine powder discharge port 50. When aspiration is performed, the inside of the centrifugal separation chamber 46 becomes negative pressure.

Further, in the cyclone type powder classification device 30 of the present embodiment, the powder to be classified stored in the hopper (not shown) is quantitatively supplied by the quantitative supply device 32, and the powder is dispersed by the dispersion device 36 as necessary. The body is dispersed in the air, and the dispersed powder-containing air is drawn into the centrifugal separation chamber 46 of the cyclone cylinder 38 through the inflow pipe 40 by the suction by the suction blower 54. At this time, as shown in FIG. 2, since the inflow tube 40 is disposed in a tangential direction with respect to the centrifugal separation chamber 46, a swirling flow R of powder and air is formed inside the centrifugal separation chamber 46. . Also, a swirling flow R of powder and air is formed inside the centrifugal separation chamber 46 by installing a discharge blower (not shown) on the upstream side of the fixed amount supply device 32 instead of the suction blower 54. .

  The cyclone-type powder classification device 30 according to an embodiment of the present invention is configured as described above, and the operation thereof will be described below.

In the cyclone type powder classification device 30 of the present embodiment, the powder to be classified (for example, powder containing a particle diameter of 30 μm or more) stored in a hopper (not shown) is discharged quantitatively by the quantitative supply device 32. The powder is dispersed in the air by the dispersing device 36 if necessary, and the air containing the dispersed powder is sucked by the suction blower 54, and the inside of the centrifugal separation chamber 46 of the cyclone cylinder 38 through the inflow pipe 40. Flowed into At this time, since the inflow tube 40 is disposed in a tangential direction with respect to the centrifugal separation chamber 46, as shown in FIG. 2, a swirling flow R of powder and air is formed inside the centrifugal separation chamber 46. Ru. Also, a swirling flow R of powder and air is formed inside the centrifugal separation chamber 46 by installing a discharge blower (not shown) on the upstream side of the fixed amount supply device 32 instead of the suction blower 54. .

  The powder exposed to the swirling flow R is dispersed by the swirling motion and is subjected to a separating action according to the particle size. As a result, fine powder of a predetermined particle size or less, for example, fine powder of less than 5 μm, is sucked into the discharge pipe 48 from the lower end opening 48a of the outflow pipe 48 opening into the centrifugal separation chamber 46 together with the air flow, and the fine powder discharge port The fine powder is recovered by the fine powder recovery unit 51 via the reference numeral 50.

On the other hand, the powder having a particle diameter of 5 μm or more (for example, 5 μm to 30 μm) is not discharged upward from the fine powder discharge port 50, and the inside of the roughly cylindrical cyclone cylinder 38 is gradually And is discharged from the lower end opening of the body leg 52 formed at the lower end of the cyclone cylinder 38 to the tapered part 53 side which spreads out. Then, the powder falling downward with the flow of the swirling flow R is guided to the inclined passage 56 between the partition walls which tapers outward on the circumferential outer side.

  At this time, a predetermined amount of air is supplied to the additional air flow introduction pipe 57 from the air compressor 63 via the flow meter 65, and the swirling flow R is generated by the additional air flow S introduced from the additional air flow introduction pipe 57. The additional air flow S is introduced so as to flow inward from the outer peripheral side of (see FIG. 2).

  When a new additional air flow S is introduced into the inter-partition inclined passage 56, as shown in FIG. 3, a flow T which is directed inward from the outer peripheral side of the flow of the swirling flow R is generated. Then, the intermediate particles m of the intermediate particles m and the coarse particles M falling into the inclined passage 56 between the partition walls have a small weight and thus rise, and then the upper end of the second cylindrical collector 55 It is introduced into the second cylindrical collector 55 through the opening 55d. Then, it is sent to the lower end opening 55c via the S-shaped passage 55a, and is separated from the lower end opening 55c.

  On the other hand, the coarse particles (for example, 30 μm or more) M among the powder falling from the lower end of the body leg 52 into the inclined passage 56 between partitions due to the swirling flow R have a large weight. It is falling in the state where the centrifugal force of. Therefore, the coarse particles M do not fly up even if they receive the flow T rising by the additional air flow S, and receive the force in the outer peripheral direction indicated by the arrow P in FIG. It falls downward along the inner wall surface of the vessel 39. As a result, the coarse particles M fall to the lower end opening 39a side of the first cylindrical collector 39, and are separated from the lower end opening 39a.

  Thus, in the present embodiment, for example, after first removing fine powder less than 5 μm outward, the intermediate particles m are collected in the second cylindrical collector 55, and the coarse particles M in the first cylinder It is possible to separate each one into the shape collector 39.

  Thereby, according to the present invention, the powder having the particle size distribution is first separated into the fine powder and the coarse powder containing the intermediate particles, and then the coarse particles M can be removed from the coarse powder containing the intermediate particles. Become.

  Thereby, an intermediate particle m having a desired particle size can be obtained.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to this.

For example, in the above-described embodiment, in order to form the swirling flow R, the air flow is introduced from the inflow pipe 40 and the air in the centrifugal separation chamber 46 is sucked or discharged by the outflow pipe 48. Is not limited to this. For example, as shown in FIG. 9, a spiral guide vane 47 is disposed inward of the cyclone cylinder 38 without using the outflow pipe 48, and the guide vane 47 guides the swirl flow into the centrifugal separation chamber 46. R can also be formed. Thus, the invention is also applicable to axial flow cyclones. In addition, although the guide blade 47 shown in FIG. 9 is installed non-rotatably, the guide blade 47 is not limited to fixed installation, You may make it rotate by external power.

  Furthermore, in the above embodiment, the body leg 52 is formed to be tapered, but the body leg 52 is not limited to being tapered, but may be formed in a substantially straight barrel shape or a divergent shape. good.

  Moreover, in said embodiment, although external air is introduced only from the inflow pipe 40, external air can also be additionally introduced from other than the inflow pipe 40. FIG.

  In such a case, as shown in FIG. 4A, the ring-shaped member 60 is installed around the upper peripheral wall 42 or the body leg 52 in such a manner as to expand the centrifugal separation chamber 46 inside. A plurality of air intake holes 62a may be formed in the ring-shaped member 60, so that external air may be positively added to the centrifugal separation chamber 46 from the air intake holes 62a.

  In this case, the air intake holes 62a formed in the ring-shaped member 60 are preferably formed in the tangential direction of the peripheral wall 61 so as to follow the flow of the swirling flow R as shown in FIG. Further, the air intake holes 62a are not limited to the same diameter, and the opening on the outside air introduction side can also be enlarged.

  With such a configuration, the speed of the swirling flow in the centrifugal separation chamber 46 can be increased by the outside air introduced from the air intake hole 62a, and as a result, the particle classification performance can be improved.

  Alternatively, in the present invention, as shown in FIG. 4 (b), the air intake nozzle 62 b for introducing the outside air into the peripheral wall 42 or the body leg 52 of the centrifugal separation chamber 46, the peripheral wall 42 of the centrifugal separation chamber 46 or It is preferable to be tangentially connected to the body leg 52 in a direction along the flow of the swirling flow R.

With such a configuration, the speed of the swirling flow R in the centrifugal separation chamber 46 can be increased by the external air introduced from the air intake nozzle 62b, and as a result, the particle classification performance can be improved. . Preferably, one or more nozzles 62b are formed. Further, when the outside air is blown from the air intake hole 62a or the air intake nozzle 62b into the centrifugal separation chamber 46 at a speed equal to or higher than the swirling speed of the swirling flow R in the direction along the swirling flow R, the classification point D _p50 is It can be made smaller.

  Further, in the present invention, as shown in FIGS. 10 (a) and 10 (b), the additional air flow introduction pipe 57 is connected in the tangential direction of the first collector 39 or the diverging tapered portion 53, It is preferable to be connected so as to increase the swirling speed of the swirling flow R of 46. Here, to connect so as to increase the swirling speed of the swirling flow R, the additional air flow introducing pipe 57 is arranged such that the swirling direction of the swirling flow U formed by the additional air flow S is the same as the swirling direction of the swirling flow R. To connect.

  With such a configuration, the additional air flow S can increase the swirling speed of the swirling flow R.

Further, as shown in FIGS. 11A and 11B, for example, an additional air flow storage chamber 67 is formed on the outer periphery of the first cylindrical collector 39 to which the additional air flow introduction pipe 57 is connected, and The air flow discharge hole 68 may be opened in the first cylindrical collector 39. Thus, after temporarily storing the additional air flow S in the additional air flow storage chamber 67, the additional air flow S can also be introduced into the cyclone cylinder 38. In this aspect, since the additional air flow storage chamber 67 is attached so as to surround the air flow discharge hole 68, when the additional air flow S flows collectively to the additional air flow storage chamber 67, the air flow discharge hole 68 And the additional air flow S is divided and supplied to the inner side of the cyclone cylinder 38 or the inner side of the first cylindrical collector 39 and is guided to the inclined passage 56 between the partition walls. Will increase.

  Further, the additional air flow storage chamber 67 is not limited to the outer periphery of the first cylindrical collector 39, and may be provided in the tapered portion 53 of the trunk leg 52.

  In the present invention, the swirling direction of the swirling flow U from the bottom to the top formed by the additional air flow S introduced from the additional air flow introduction pipe 57 is formed from the top to the bottom formed in the centrifugal separation chamber 46. The introduction direction of the additional air flow S is set so as to be the same as the swirling direction of the swirling flow R toward the, and the swirling speed of the swirling flow R <the swirling speed of the swirling flow U at the lower outlet of the inclined passage 56 between partitions. Preferably, it can be set to be In this aspect, the swirling flow U can accelerate the swirling speed of the swirling flow R containing powder.

Further, inlet tube 40 which communicates with the centrifugal separation chamber 46, as shown in FIG. 6, the portion which communicates with the centrifugal chamber 46, X ₁ is preferably narrower than the opening X ₀ of the inlet side .

According to such another embodiment of the present invention, the powder remaining in the cyclone cylinder 38 can be further classified into an intermediate particle m and a coarse particle M.

  In the present invention, it was confirmed that when the height position of the second cylindrical collector 55 is made downward and thereby the distance δ shown in FIG. 1 is increased, more coarse particles M are removed. .

Also, as shown in FIG. 6, when the opening ratio G = X ₁ / X ₀ decreases, the coarse particles M affected by the centrifugal force of the swirling flow R in the centrifugal separation chamber 46 are affected by the additional air flow S. Since it becomes difficult to receive, it has been confirmed that the coarse particles M tend to be collected to the lower end opening 39a side of the first cylindrical collector 39.

  In the present invention, as shown in FIG. 7, the straight line in the vertical direction is directed from the inner peripheral wall of the lower end opening of the body leg 52 toward the inclined surface 55b of the second cylindrical collector 55. When the position where this straight line intersects with the inclined surface 55b is E, the length x extending from the position E to the outside of the inclined surface 55b (provided that the straight line does not intersect with the inclined surface 55b). The length of the inclined surface 55b is x), and the length of the inclined surface 53a of the tapered portion 53 of the first cylindrical collector 39 is y, preferably 0.05y ≦ x <y. It is confirmed that the classification accuracy is improved by setting 0.14 y ≦ x <y, more preferably 0.54 y ≦ x <y, more preferably.

  If the xy relationship is in the above-mentioned preferable range, it is considered that the drag of the additional air flow is increased more than the centrifugal force by the swirling flow R acting on the particles with the increase of the additional air flow, and classification with an increased classification point can be performed.

  Further, in the method of the present invention, the swirling flow U from the bottom to the top formed by the additional air flow S introduced from the additional air flow introduction pipe 57 is formed from the top to the bottom in the centrifugal separation chamber 46. The additional air flow S is introduced to be in the same direction as the swirling flow R toward the, and classification is performed such that the swirling speed of the swirling flow R <the swirling speed of the swirling flow U at the lower outlet of the inclined passage 56 between partitions. You can In this method, it is possible for the swirling flow U to accelerate the swirling speed of the swirling flow R containing powder.

  According to the method of the present invention in which the swirling velocity of the swirling flow R and the swirling velocity of the swirling flow U are in the above-mentioned relationship in an apparatus in which the xy relationship is in the above further preferable range, The centrifugal force due to the swirling flow R is added to the centrifugal force due to the swirling flow U of the additional air flow, and the centrifugal force also increases with the increase of the drag of the additional air flow, and the difference between the drag force and the centrifugal force acting on the particles It is considered to be large, and the classification accuracy can be remarkably improved without changing the particle diameter of the classification point very much.

  In order to set the swirling speed of the swirling flow R <the swirling speed of the swirling flow U, the additional air flow S, the air introduced into the centrifugal separation chamber 46 through the inflow pipe 40, the air intake hole 62a It is preferable to adjust the flow rate of at least one of the external air taken in from the air and the air taken in from the air intake nozzle 62b. Further, as a method of preparing the additional air flow S, as described above, connecting the additional air flow introduction pipe as shown in FIG. 10 (a), (b) or FIG. 11 (a), (b) may be mentioned. .

In the present invention, as shown in FIG. 18, a ratio (r ₂₎ between the radius r ₁ of the lower end opening of the body leg 52 and the radius r ₂ of the upper end opening of the second cylindrical collector 55 / R ₁ ) is preferably 0 <r ₂ / r ₁ ≦ 1.30, more preferably 0 <r ₂ / r ₁ ≦ 1.00, still more preferably 0 <r ₂ / r ₁ ≦ 0.79, It was confirmed that the classification point D _p50 of the particles to be classified can be reduced as 0 <r ₂ / r ₁ ≦ 0.53 is most preferable. If r ₂ / r ₁ is in the above range, an air flow having a high swirling speed of the swirling flow R in the centrifugal separation chamber 46 will be guided to the inclined passage 56 between the partition walls, and Since the centrifugal force acting on the particles is larger than the drag force acting on the particles of the additional air flow S introduced from the air flow introduction pipe 57, it is considered that the classification point D _p50 becomes smaller.

While making the value of r ₂ / r ₁ into the above range, the outside air from the air intake hole 62 a or the air intake nozzle 62 b shown in FIG. Thus, it was confirmed that blowing into the centrifugal separation chamber 46 further enhances the effect of reducing the classification point of the particles to be classified.

  Furthermore, when the amount of the additional air flow S from the additional air flow introduction pipe 57 is increased, it is confirmed that the drag of the air flow contributes to causing the intermediate particles m to fly up, and the classification performance is improved.

  In addition, when the flow rate from the inflow pipe 40 is small, the centrifugal force acting on the coarse particles M becomes weak, and the drag of the additional air flow S becomes larger. That is, the influence on the reduction of the classification performance of the coarse particles M is increased. On the contrary, it has been confirmed that when the flow rate from the inflow pipe 40 is large, the influence of the drag of the additional air flow S acting on the coarse particles M is reduced.

According to the present invention, since large coarse particles M can be classified in one cyclone cylinder 38, as a result, it is possible to classify the coarse particles, the intermediate particles, and the fine particles into three stages.

  The results of examining how the raw material classification is performed when using the cyclone-type powder classification device shown in FIG. 1 will be described below.

In Examples 2 to 22, the particle diameter was measured by a laser diffraction / scattering type (measuring device: LA-950 manufactured by Horiba, Ltd.).
Example 1
[Raw material X]
Material: Acrylic resin Average particle size: 22 μm
True density: 1190 kg / m ³
Percentage of particles less than 5 μm to less than 30 μm: 96.9%
Particles of 30 μm or more: 3%
(0.1% less than 5 μm)
The frequency distribution of the raw material X is shown to Fig.8 (a).

[Classification condition]
Flow rate from the inflow pipe 40: Q = 800 (L / min)
Separation distance of second cylindrical collector (FIG. 7): δ = 11 mm
Flow from the additional air flow introduction pipe 57: q = 90 (L / min)
Classification point by second cylindrical collector: 30 μm

[Experimental result]
The proportion of particles of 30 μm or more in the intermediate particles (5 μm to 30 μm) was 0.3%.
The intermediate particle recovery rate at that time was 90%.
The frequency distribution of the obtained intermediate particles and coarse particles is shown in FIG. 8 (b), and the material balance is shown in FIG. 8 (c).
In addition, in FIG.8 (b), the black circle marker line has shown the frequency distribution by the side of an intermediate particle, and the white circle marker line has the coarse particle side.

[Discussion]
It can be seen that when the intermediate particles are compared with the raw material X, the particle abundance ratio of 30 μm or more is greatly reduced. It was confirmed that the intermediate particle recovery rate in that case was also maintained at a relatively high level of 90% or more.

Example 2
<Cyclone type powder classification device (configuration of FIG. 1)>
Diameter of upper cylinder of cyclone tube : 72 mm
Length of upper cylinder of cyclone tube : 168 mm
Radius r ₁ : 19 mm of the lower end opening of the body leg of the cyclone tube
Length of body leg of cyclone tube : 215 mm
Length y of tapered section inclined surface of first cylindrical collector: 42 mm
When a straight line in the vertical direction is extended from the inner circumferential wall of the lower end opening of the body leg toward the inclined surface of the second cylindrical collector, and the position where this straight line intersects with the inclined surface is E, Length x (hereinafter also referred to as “length x”) extending from position E to the outside of the inclined surface: 6 mm
The diameter of the lower end opening of the cylindrical part of the first cylindrical collector: 35 mm
Length of cylindrical part of first cylindrical collector: 208 mm
Length of inclined surface 55b of second cylindrical collector: 6 mm
Radius r ₂ of the upper end opening of the second cylindrical collector: 19 mm
Diameter of lower end opening of cylindrical part of second cylindrical collector: 35 mm
Length of cylindrical part of second cylindrical collector: 97 mm
Position of additional air flow introducing pipe: Aspect shown in FIG. 10 Swirling direction of swirling flow U formed by additional air flow S: Direction G same as the swirling direction of swirling flow R formed in the centrifugal separation chamber (aperture ratio shown in FIG. 6 ): 0.4
θ (inclination of the inclined surface of the tapered portion of the first cylindrical collector shown in FIG. 1): 47 °
δ (separation distance of second cylindrical collector shown in FIG. 1): 11 mm
Number of additional air flow introduction tubes: 1
Inner diameter of additional air flow introduction pipe: 6φ
Attachment angle of additional air flow introduction pipe: 20 °

[Raw material Y]
Material: Acrylic particle average particle size: 27 μm
True density: 1190 kg / m ³
Particle size width of particle size distribution: 17 to 40 μm
Frequency distribution of the raw material Y: As shown in FIG. 12, the raw material Y is discharged by the quantitative supply device 32, and the powder is dispersed in the air flow by the dispersing device 36 (ring nozzle jet type dispersing device manufactured by Nisshin Engineering Co., Ltd.) The air was sucked by the blower 54 and introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at a flow rate Q = 600 (L / min) from the inflow pipe 40 together with air. Powder was recovered from the fine powder outlet 50, the lower end opening 39a of the first cylindrical collector, and the lower end opening 55c of the second cylindrical collector.

Example 3
The same procedure as in Example 2 was carried out except that an additional air flow S with a flow rate q = 40 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 4
The process was performed in the same manner as in Example 2 except that an additional air flow S of q = 50 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 5
The raw material Y was introduced together with air at Q = 800 (L / min) from the inflow pipe 40 to the centrifugal separation chamber of the cyclone cylinder 38, and the additional air flow S of q = 60 (L / min) was introduced to the additional air flow introduction pipe 57 The same procedure as in Example 2 was followed except for the following.

Example 6
The raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air, and the additional air flow S of q = 80 (L / min) is introduced to the additional air flow introduction pipe 57 The same procedure as in Example 2 was followed except for the above.

Example 7
The raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 with air at Q = 800 (L / min), and the additional air flow S of q = 90 (L / min) is introduced to the additional air flow introduction pipe 57 The same procedure as in Example 2 was followed except for the above.

Example 8
The same operation as in Example 2 was performed using the same cyclone-type powder classification device as in Example 2 except that the length x was 23 mm.

Example 9
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. The operation was performed in the same manner as in Example 2 except that an additional air flow S of q = 20 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 10
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. The operation was performed in the same manner as in Example 2 except that an additional air flow S of q = 40 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 11
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. The operation was performed in the same manner as in Example 2 except that an additional air flow S of q = 50 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 12
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. The operation was performed in the same manner as in Example 2 except that an additional air flow S of q = 60 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 13
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. The operation was performed in the same manner as in Example 2 except that an additional air flow S of q = 80 (L / min) was introduced into the additional air flow introduction pipe 57.

Example 14
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. The operation was performed in the same manner as in Example 2 except that the raw material Y was introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air.

Example 15
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. In operation, the raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air, and an additional air flow of q = 20 (L / min) to the additional air flow introduction pipe 57 The same procedure as in Example 2 was performed except that S was introduced.

Example 16
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. In operation, the raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air, and an additional air flow of q = 40 (L / min) to the additional air flow introduction pipe 57 The same procedure as in Example 2 was performed except that S was introduced.

Example 17
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. In operation, the raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air, and an additional air flow of q = 60 (L / min) to the additional air flow introduction pipe 57 The same procedure as in Example 2 was performed except that S was introduced.

Example 18
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. In operation, the raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air, and an additional air flow of q = 80 (L / min) to the additional air flow introduction pipe 57 The same procedure as in Example 2 was performed except that S was introduced.

Example 19
The same cyclone-type powder classification device as in Example 2 was used except that the length x was 23 mm. In the operation, the raw material Y is introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow pipe 40 at Q = 800 (L / min) together with air, and an additional air flow of q = 100 (L / min) to the additional air flow introduction pipe 57 The same procedure as in Example 2 was performed except that S was introduced.

[Experimental result]
The relationship between the particle diameter which is a classification result and partial separation efficiency is shown in FIGS. Here, the partial separation efficiency .DELTA..eta, represented by the following formula (1), from D _p -1 / 2ΔD _p present in the feed Y D _p + 1 / 2ΔD _p ranges first with respect to the weight of the particle diameter of the in which a tubular collector in the collected D _p -1 / 2ΔD _p was determined D _p + 1 / 2ΔD _p weight ratio of the particle size in the range of.

(In the formula (1), .DELTA..eta partial separation efficiency, m _o is the mass of raw material Y supplied to the cyclone tube, f _o is the frequency distribution of the material Y, the m _c is collected in the first tubular collector The mass of all particles, f _c is the frequency distribution of all particles collected by the first cylindrical collector, and D _p is the particle size.)

  The relationship between the particle diameter and the partial separation efficiency determined from the results of Examples 5 to 7 is shown in FIG.

  The relationship between the particle diameter and the partial separation efficiency determined from the results of Examples 8 to 13 is shown in FIG.

  The relationship between the particle diameter and the partial separation efficiency determined from the results of Examples 14 to 19 is shown in FIG.

In FIGS. 13 to 16, E _c = 100 * m _c / m _o (where m _c is the mass of all particles collected by the first cylindrical collector, and m _o is the raw material Y supplied to the cyclone cylinder. Represents the mass of

[Discussion]
It can be understood from FIGS. 13 to 16 that, in the apparatus of the present invention, as the flow rate q of the additional air flow S from the additional air flow introduction pipe is increased, the slope of the curve showing the partial separation efficiency is larger and the classification accuracy is improved. . The reason is that the additional air flow introducing pipe 57 is connected so as to increase the swirling speed of the swirling flow in which the additional air flow S to be introduced is guided to the inclined flow passage 56 between partitions, thereby increasing q It is considered that this is because the swirling speed of the swirling flow R guided to the inclined passage 56 between partition walls is further increased, and the influence on classification is increased.

  Further, from the comparison between FIG. 13 and FIG. 14 and the comparison between FIG. 15 and FIG. 16, in the apparatus of the present invention, the raw material Y is supplied at a flow rate Q = 800 (L / min) from the inflow pipe together with air. It can be seen that the slope of the curve showing the partial separation efficiency is larger than in the case of supplying at Q = 600 (L / min), and the classification accuracy is improved. The reason is that the increase in Q causes the flow velocity at the cyclone inlet to increase, the number of particles entering the inter-partition inclined passage 56 increases, and the effect of centrifugal acceleration is large when particles enter the inter-partition inclined passage 56 The difference in centrifugal force between coarse particles of 30 μm or more and fine particles with small centrifugal acceleration spreads, and it is considered that the drag by the additional air flow S acts more effectively in separating and removing coarse particles with high accuracy. Be

  From comparison of FIGS. 13 to 14 with FIGS. 15 to 16, when the length x is 23 mm, the slope of the curve indicating the partial separation efficiency is larger than when the length x is 6 mm, It can be seen that the classification accuracy is enhanced. The reason is that if the length x is 6 mm, the drag of the additional air flow S is considered to mainly act on classification, and if the flow rate q of the additional air flow S is increased, the classification point becomes larger, and particularly coarse particles are removed On the other hand, in the embodiment of length x = 23 mm, the centrifugal force by the swirling flow U of the additional air flow S is added to the centrifugal force of the swirling flow R when the flow rate q of the additional air flow S is increased. The centrifugal force also increases with the increase, and the particle diameter at the classification point does not change, but it is considered that the classification accuracy is further improved.

The relationship between the flow rate q of the additional air flow S and the classification accuracy index κ calculated from FIG. 15 is shown in FIG. Here, the classification accuracy index κ is expressed by ₌₌ D _p25 / D _p75 if the particle diameters when the partial separation efficiencies of the partial separation efficiency curve are 0.25 and 0.75 are D _{p 25} and D _{p 75} , respectively. Is an index that represents classification accuracy. As the value is larger, the slope of the partial separation efficiency curve in FIG. 15 is larger, and the classification accuracy is higher. In the devices of Examples 14 to 19 in which the length x is 23 mm, the swirling direction of the swirling flow R and the swirling direction of the swirling flow U are in the same direction, and the additional air flow introduction pipe is as shown in FIGS. It was confirmed that the value of the classification accuracy index 大 き く increases to reach 0.9 when the swirling velocity of the swirling flow U of the additional air flow S guided to the inclined passage between partition walls is significantly increased by connecting as described above. In FIG. 17, when the flow rate q of the additional air flow S is increased, the value of の tends to rapidly increase from about 0.75 to reach 0.9 from around q = 50 (L / min). This is because the swirling flow U of the additional air flow S accelerates the swirling speed of the swirling flow R containing the powder flowing from the centrifugal separation chamber 46 through the lower end opening of the body leg 52 and into the inclined passage 56 between partitions. It is. This effect is obtained by setting the swirling flow R and the swirling flow U in the same direction as the swirling flow R, ie, the lower outlet of the inter-partition inclined passage 56 where the swirling flow R exits from the inter-partition inclined passage 56 It can be achieved by satisfying the following conditions at the confluence point with the swirling flow U.
Swirling speed of the swirling flow R <swirling speed of the swirling flow U By the way, in a general classifier, classification is good with κ = 0.5 to 0.7, and classification is good with κ> 0.7. The performances of the cyclone type powder classification devices of Examples 14 to 19 show extremely high performance.

Example 20
<Cyclone type powder classification device (configuration of FIG. 1)>
Diameter of upper cylinder of cyclone tube : 72 mm
Length of upper cylinder of cyclone tube : 168 mm
Radius r ₁ : 19 mm of the lower end opening of the body leg of the cyclone tube
Length of body leg of cyclone tube : 215 mm
Length of tapered section inclined surface of the first cylindrical collector: 42 mm
The diameter of the lower end opening of the cylindrical part of the first cylindrical collector: 35 mm
Length of cylindrical part of first cylindrical collector: 208 mm
Length of inclined surface of second cylindrical collector: 23 mm
When a straight line in the vertical direction is extended from the inner circumferential wall of the lower end opening of the body leg toward the inclined surface of the second cylindrical collector, and the position where this straight line intersects with the inclined surface is E, Length x (hereinafter also referred to as “length x”) extending from position E to the outside of the inclined surface: 23 mm
Radius r ₂ of the upper end opening of the second cylindrical collector: 19 mm
Diameter of lower end opening of cylindrical part of second cylindrical collector: 35 mm
Length of cylindrical part of second cylindrical collector: 97 mm
Position of additional air flow introducing pipe: Aspect shown in FIG. 10 Swirling direction of swirling flow U formed by additional air flow S: Direction G same as the swirling direction of swirling flow R formed in the centrifugal separation chamber (aperture ratio shown in FIG. 6 ): 0.4
θ (inclination of the inclined surface of the tapered portion of the first cylindrical collector shown in FIG. 1): 47 °
δ (separation distance of second cylindrical collector shown in FIG. 1): 11 mm
Number of additional air flow introduction tubes: 1
Inner diameter of additional air flow introduction pipe: 6φ
Attachment angle of additional air flow introduction pipe: 20 °

[Raw material Y]
Material: Acrylic particle average particle size: 27 μm
True density: 1190 kg / m ³
Particle size width of particle size distribution: 17 to 40 μm
Frequency distribution of the raw material Y: As shown in FIG. 12, the raw material Y is discharged by the quantitative supply device 32, and the powder is dispersed in the air flow by the dispersing device 36 (ring nozzle jet type dispersing device manufactured by Nisshin Engineering Co., Ltd.) The air was drawn by the blower 54 and introduced into the centrifugal separation chamber of the cyclone cylinder 38 from the inflow tube 40 at a flow rate Q = 800 (L / min) from the inflow tube 40 together with air. Powder was recovered from the fine powder outlet 50, the lower end opening 39a of the first cylindrical collector, and the lower end opening 55c of the second cylindrical collector.

Example 21
The same operation as in Example 20 was performed using the same cyclone-type powder classification device as in Example 20, except that the radius r ₂ of the upper end opening of the second cylindrical collector was set to 15 mm.

Example 22
The same operation as in Example 20 was performed using the same cyclone-type powder classification device as in Example 20, except that the radius r ₂ of the upper end opening of the second cylindrical collector was 10 mm.

[Experimental result]
The relationship between the particle diameter which is a classification result of Examples 20-22, and partial separation efficiency is shown in FIG. And the radius r ₂ of the upper end opening portion of the second cylindrical collector 55 will be smaller than the radius r ₁ of the lower end opening of the body foot portion 52 of the centrifuge chamber 46, the portion representing the classification point The particle diameter D _p50 decreases when the separation efficiency is 0.5.

In FIG. 19, since the raw material powder does not contain particles smaller than 17 μm, the partial separation efficiency curve at r ₂ = 10 mm rises with a steep slope. If particles smaller than 17 μm are contained in the raw material powder, it is considered possible to make the classification point D _p50 smaller than 17 μm.
[Discussion]
The swirling flow R in the centrifugal separation chamber 46 is a free vortex which increases as the swirling speed approaches the center of the centrifugal separation chamber 46.

Therefore, either the radius r ₂ of the upper end opening portion of the second cylindrical collector 55 equal to the radius r ₁ of the lower end opening of the body the body foot portion 52 of the centrifuge chamber 46, when smaller than the radius r ₁ An air flow having a high swirling speed of the swirling flow R in the centrifugal separation chamber 46 is guided to the inclined passage 56 between the partition walls. As a result, it is considered that the centrifugal force acting on the particles becomes larger than the drag force acting on the particles of the additional air flow S introduced from the additional air flow introduction pipe 57 in the inclined passage 56 between partition walls, and the classification point D _p50 becomes smaller. Be

Reference Signs List 30 cyclone type powder classification device 32 fixed amount supply device 36 dispersing device 38 cyclone cylinder 39 first cylindrical collector 39a lower end opening 40 inflow pipe 42 upper peripheral wall 43 opening 46 centrifugal separation chamber 48 outflow pipe 48a lower end opening 50 fine powder Discharge port 51 Fine powder collection portion 52 Body leg portion 53 Spreading tapered portion 53a Sloped surface 54 Suction blower 55 Second cylindrical collector 55a S-shaped passage 55b Sloped surface 55c Lower end opening 55d Upper end opening 56 Between partitions Inclined passage 57 additional air flow introduction pipe 60 ring-shaped member 61 peripheral wall 62a hole 62b nozzle 64 valve 66 valve 67 additional air flow storage chamber 68 air flow discharge hole M coarse particles m intermediate particles R of a predetermined weight or less additional air flow additional air flow

Claims (13)

A cylindrical upper peripheral wall (42),
A body leg (52) connected to a lower portion of the upper peripheral wall (42);
A first cylindrical collector (39) is provided at the lower part of a substantially cylindrical cyclone cylinder (38) having a flared tapered part (53) connected to the lower part of the body leg (52),
The powder having a particle size distribution is supplied via an inflow pipe (40) into a centrifugal separation chamber (46) formed between the upper peripheral wall (42) and the body leg (52). With
The centrifugal separation chamber (46) is located by suctioning or discharging air in the centrifugal separation chamber (46) through an outflow pipe (48) located above the centrifugal separation chamber (46) and communicating with the outside. In a cyclone-type powder classification device, in which a swirling flow (R) is formed and the powder is separated into fine powder and coarse powder by the swirling flow (R),
It is arranged straddling between the tapered portion (53) and the first cylindrical collector (39), the upper end portion is opened, and the fine particles separated from the opening portion of the lower end portion are passed (55a) The inclined surface which has a structure which takes out from the 2nd cylindrical collector (55) through, and is arranged to face so that a flow path is formed to the inclined surface (53a) of the taper part (53). (55b) at the top, between the dividing walls the inclined passage (56) between the inclined surface (53a) of the tapered portion (53) and the inclined surface (55b) of the second cylindrical collector (55). A second cylindrical collector (55), which is tapered at the top, forming
An additional air flow introducing pipe connected to the side wall of the first cylindrical collector (39) or the side wall of the tapered portion (53) for introducing an additional air flow (S) into the centrifugal separation chamber (46) And (57), and
The coarse powder guided downward with the swirling flow (R) in the centrifugal separation chamber (46) is guided from the lower end opening of the body leg (52) to the inclined passage (56) between the partition walls While
By means of the additional air flow (S) introduced into the centrifugal separation chamber (46) from the additional air flow introduction pipe (57), the intermediate particles (m) having a weight not larger than a predetermined weight contained in the coarse powder are ) From the outer peripheral side of the inner side to the inner peripheral direction, whereby the intermediate particles (m) less than the predetermined weight are moved inward through the upper end opening (55d) of the second cylindrical collector (55). Intermediate particles (m) having a weight equal to or less than the predetermined weight are separated from the lower end opening (55c) of the second cylindrical collector (55) ,
A straight line in the vertical direction is extended from the inner peripheral wall of the lower end opening of the body leg (52) toward the inclined surface (55b) of the second cylindrical collector (55), and this straight line and the inclined surface Assuming that the position intersecting with (55b) is (E), the length extending from the position (E) to the outside of the inclined surface (55b) is (x) (where the straight line and the inclined surface (55b) If the length of the inclined surface (55b) is (x), the length of the inclined surface (53a) of the tapered portion (53) of the first cylindrical collector (39) Let (y) be
0.05 y ≦ x <y
Cyclone powder classifying device characterized by being configured. A cylindrical upper peripheral wall (42),
A body leg (52) connected to a lower portion of the upper peripheral wall (42);
A first cylindrical collector (39) is provided at the lower part of a substantially cylindrical cyclone cylinder (38) having a flared tapered part (53) connected to the lower part of the body leg (52),
The powder having a particle size distribution is supplied via an inflow pipe (40) into a centrifugal separation chamber (46) formed between the upper peripheral wall (42) and the body leg (52). With
A spiral guide vane (47) is disposed inward of the cyclone cylinder (38), and the guide vane (47) generates a swirling flow (R) in the centrifugal separation chamber (46), and the swirling In a cyclone-type powder classification device that separates the powder into fine powder and coarse powder by stream (R),
It is arranged straddling between the tapered portion (53) and the first cylindrical collector (39), the upper end portion is opened, and the fine particles separated from the opening portion of the lower end portion are passed (55a) The inclined surface which has a structure which takes out from the 2nd cylindrical collector (55) through, and is arranged to face so that a flow path is formed to the inclined surface (53a) of the taper part (53). (55b) at the top, between the dividing walls the inclined passage (56) between the inclined surface (53a) of the tapered portion (53) and the inclined surface (55b) of the second cylindrical collector (55). A second cylindrical collector (55), which is tapered at the top, forming
An additional air flow introducing pipe connected to the side wall of the first cylindrical collector (39) or the side wall of the tapered portion (53) for introducing an additional air flow (S) into the centrifugal separation chamber (46) And (57), and
The coarse powder guided downward with the swirling flow (R) in the centrifugal separation chamber (46) is guided from the lower end opening of the body leg (52) to the inclined passage (56) between the partition walls While
By means of the additional air flow (S) introduced into the centrifugal separation chamber (46) from the additional air flow introduction pipe (57), the intermediate particles (m) having a weight not larger than a predetermined weight contained in the coarse powder are ) From the outer peripheral side of the inner side to the inner peripheral direction, whereby the intermediate particles (m) less than the predetermined weight are moved inward through the upper end opening (55d) of the second cylindrical collector (55). Intermediate particle (m) having a weight equal to or less than the predetermined weight is separated from the lower end opening (55c) of the second cylindrical collector (55). A straight line in the vertical direction is extended from the inner peripheral wall of the lower end opening of the body leg (52) toward the inclined surface (55b) of the second cylindrical collector (55), and this straight line and the inclined surface Assuming that the position intersecting with (55b) is (E), the length extending from the position (E) to the outside of the inclined surface (55b) is (x) (where the straight line and the inclined surface (55b) If the length of the inclined surface (55b) is (x), the length of the inclined surface (53a) of the tapered portion (53) of the first cylindrical collector (39) Let (y) be
  0.05 y ≦ x <y
The cyclone type powder classification device according to claim 2, characterized in that The cyclone type powder classification device according to any one of claims 1 to 3, wherein a plurality of the additional air flow introduction pipes (57) are formed at predetermined intervals in a circumferential direction. The said additional air flow introductory pipe (57) is connected so that it may have a flow which faces inward from the outer peripheral side of the said swirling flow (R), The any one of Claim 1 to 4 characterized by the above-mentioned. Cyclone-type powder classifier. The additional air flow introducing pipe (57) is connected in the tangential direction of the first cylindrical collector (39) or the diverging tapered portion (53) so as to increase the swirling speed of the swirling flow (R). The cyclone type powder classification device according to any one of claims 1 to 5 , characterized in that: The outer periphery of the first cylindrical collector (39) to which the additional air flow introducing pipe (57) is connected or the outer periphery of any one of the tapered portions (53) to which the additional air flow introducing pipe (57) is connected Form an additional air flow reservoir (67),
After the additional air flow (S) is temporarily gathered in the additional air flow storage chamber (67), the cyclone tube (S) is further provided via the air flow discharge hole (68) formed in the additional air flow storage chamber. The cyclone-type powder classification according to any one of claims 1 to 6 , which is supplied to the inside of 38) or the inside of the first cylindrical collector (39). apparatus. The swirling direction of the swirling flow (U) from the bottom to the top formed by the additional air flow (S) introduced from the additional air flow introduction pipe (57) is formed in the centrifugal separation chamber (46) The introduction direction of the additional air flow (S) is set to be the same as the swirling direction of the swirling flow (R) from the top to the bottom, and at the lower exit of the inclined passage (56) between the partition walls,
The cyclone type powder classification device according to any one of claims 1 to 7 , wherein the swirling speed of the swirling flow (R) can be set so as to be less than the swirling speed of the swirling flow (U). The inflow tube (40) communicates with the centrifugal separation chamber (46) through an opening (43) formed in the upper peripheral wall (42) of the centrifugal separation chamber (46) and the centrifugal separation chamber (46). The cyclone type powder classification device according to any one of claims 1 to 8 , wherein the cyclone type powder classification device is connected in a tangential direction with respect to 46). A plurality of air intake holes (62a) for introducing outside air into the centrifugal separation chamber (46) are formed in the upper peripheral wall (42) or the body leg (52) of the centrifugal separation chamber (46) The cyclone type powder classification device according to any one of claims 1 to 9 , characterized in that: The upper peripheral wall (42) or the body leg (52) of the centrifugal separation chamber (46) is characterized in that one or more air intake nozzles (62b) for introducing outside air are formed. The cyclone type powder classification device according to any one of claims 1 to 10 . The body foot portion (52) the ratio (r ₂ / r ₁₎ is 0 <r of the radius r ₁ of the lower end opening and the radius r ₂ of the upper end opening portion of the second tubular collector (55) of The cyclone type powder classification device according to any one of claims 1 to 11, wherein ₂ / r _{1 1.} 1.30. A device according to any one of claims 1 to 12
The swirling direction of the swirling flow (U) from the bottom to the top formed by the additional air flow (S) introduced from the additional air flow introduction pipe (57) is formed in the centrifugal separation chamber (46) An additional air flow (S) is introduced in the same direction as the swirling direction of the swirling flow (R) from the top to the bottom, and at the lower outlet of the inclined passage (56) between the partition walls,
A powder classification method, wherein the swirling speed of the swirling flow (R) <the swirling speed of the swirling flow (U).

Images