WO2006126577A1

WO2006126577A1 - Airflow classification machine and classification plant

Info

Publication number: WO2006126577A1
Application number: PCT/JP2006/310332
Authority: WO
Inventors: Hiroichi Kawasaki
Original assignee: Nippon Pneumatic Manufacturing Co., Ltd.
Priority date: 2005-05-26
Filing date: 2006-05-24
Publication date: 2006-11-30
Also published as: JP2007000862A; JP4818807B2

Abstract

An airflow classification machine capable of precisely and accurately classifying powder. A classification plate (7) is placed in a casing (2), a coarse- powder discharge opening (8) is formed around the outer periphery of the classification plate (7), and a fine-powder discharge tube (12) is connected to a fine-powder suction opening (11) provided at the center of the classification plate (7). The casing (2) has a skirt section (14) forming a first classification chamber (13) between itself and an outer peripheral portion of the upper side of the classification plate (7), and has a circular tube section (15) forming, in the bore of the skirt section (14), a second classification chamber (16) coaxial with the first classification chamber (13). Ejection nozzles (33) are arranged equidistantly around the first classification chamber (13). Fluid of a solid-air mixture is ejected from each of the ejection nozzles (33) in the circumferential direction of the outer periphery of the primary classification chamber (13), and the mixture is caused to swirl in the primary classification chamber (13) to centrifugally separate powder into coarse powder and intermediate powder that contains fine powder. The intermediate powder is raised while being swirled along peripheral wall inner surface of the secondary classification chamber (16), and moved radially inward along a ceiling surface while being caused to form a strong downward swirl at the center of the secondary classification chamber (16). Thus, the powder is centrifugally separated into the intermediate powder and the fine powder, and the fine powder is sucked into the fine powder discharge tube (12).

Description

Specification

Airflow classifier and classification plant

Technical field

TECHNICAL FIELD [0001] The present invention relates to an airflow classifier and a classification plant that classify powder such as developing toner for a copying machine into fine powder and coarse powder.

Background art

[0002] Conventionally, a power classifier described in Patent Document 1 is known as an air classifier that rotates powder at a high speed and centrifuges it into fine powder and coarse powder.

FIG. 13 shows an airflow classifier described in Patent Document 1. This airflow classifier is provided with a classification plate 81 inclined in an upward gradient from the outer periphery toward the center in the casing 80, and a classification cover 82 is provided on the classification plate 81, and the classification cover 82 and the classification plate 81 A plurality of louvers are annularly arranged on the peripheral wall of the classification chamber 83 formed between them, and an inflow passage 84 is provided between the adjacent louvers to allow secondary air to swirl into the classification chamber 83.

[0004] In addition, a powder guide cylinder 85 is provided at the upper part of the casing 80, and a powder supply cylinder 86 facing in a tangential direction is provided on the outer periphery of the powder guide cylinder 85, and the powder supply cylinder 86 Supplying a solid-gas mixed fluid of powder and compressed air into the guide cylinder 85, and supplying the powder falling around the outer periphery of the powder guide cylinder 85 while rotating around the classification cover 82 It is swirled into the classification chamber 83 from the port 87, and the swirl speed of the powder is accelerated by the secondary air flowing into the classification chamber 83 from the inflow path 84, and the powder is centrifuged into fine powder and coarse powder. Then, the fine powder moving to the center of the classification chamber 83 is sucked into the fine powder discharge cylinder 88 connected to the center of the classification plate 81.

[0005] Further, the coarse powder swirling around the outer periphery of the classification chamber 83 is discharged from a coarse powder discharge port 89 formed on the outer periphery of the classification plate 81.

Patent Document 1: JP-A-11 138103

Disclosure of the invention

Problems to be solved by the invention

[0006] By the way, in the conventional airflow classifier, the powder is swirling in the classification chamber 83. The secondary air is introduced into the classification chamber from the inflow channel 84, and the rotational speed of the powder is accelerated by the secondary air. The swirling vortex is disturbed by the confluence of the swirling air flow, and the powder cannot be swirled cleanly at high speed, so that coarse powder can easily be mixed into the fine powder and sharp classification cannot be performed! / The point which should be improved, etc. was left.

[0007] Further, in order to classify the powder in the single classification chamber 83, if the height of the classification chamber is increased or the volume is increased by increasing the inner diameter, the powder in the classification chamber 83 is increased. Since the swirling speed decreases and the powder cannot be accurately centrifuged, it is necessary to classify the powder in a restricted small volume classification chamber with a high mixing ratio of powder and air. . For this reason, it cannot be said that the classification accuracy is good, and there are still points to be improved in improving the classification accuracy.

[0008] Further, since it is necessary to accelerate the swirling airflow by sucking secondary air into the classification chamber 83 by suction, the amount of air in the classification chamber increases, and a blower that applies a suction force to the fine powder discharge cylinder 88 For example, it is necessary to use a large airflower with a large air volume, and a cyclone separator that separates the mixed fluid conveyed by air from the fine powder discharge cylinder 88 into fine powder and air, and powder from the air after separation. Since accessories such as bag filters that collect water must be increased in proportion to the air volume, the equipment costs increase, and there are still points to be improved in order to reduce the costs.

[0009] Generally, toner used in an image forming apparatus such as a copying machine cannot form a clear image if it contains particles larger than necessary or smaller than necessary. . Therefore, in the toner production plant, the fine powder classified by the first air flow classifier is supplied to the second air flow classifier, and the fine powder is classified into fine powder and ultra fine powder. It is a product.

[0010] In addition, when two air classifiers are connected to the series and a multi-product classification is performed in which the powder is classified into various types of coarse powder, fine powder, and ultrafine powder, In this way, since a large amount of secondary air is required for one air classifier, the two air classifiers are connected to the tandem and the fine powder classified by the first air classifier is used. It becomes difficult to carry out continuous classification by sending it to the second air classifier. [0011] Therefore, conventionally, fine powder classified by the first air classifier is once collected.

Since the fine powder was processed off-line again with a second airflow classifier installed separately, the equipment cost was high.

[0012] An object of the present invention is to provide an airflow classifier and a classification plant that can classify powder sharply and with high accuracy and can reduce facility costs and running costs. It is.

Means for solving the problem

[0013] In order to solve the above-described problems, in the airflow classifier according to the present invention, a classification plate is provided in a casing, and a substantially cylindrical primary surface is provided on the outer periphery of the upper surface of the classification plate in the casing. A classification chamber and a substantially cylindrical or conical secondary classification chamber having a smaller diameter than the primary classification chamber are formed on the same axis as the primary classification chamber, and the outer peripheral portion of the primary classification chamber is formed on the peripheral wall of the primary classification chamber. An injection nozzle that injects a solid-gas mixed fluid of powder and compressed air toward the circumferential direction is provided, a coarse powder discharge port is formed between the outer periphery of the classification plate and the inner peripheral surface of the casing, and the center of the classification plate A configuration in which a fine powder discharge cylinder is connected to a fine powder suction port formed in the section is adopted.

[0014] Here, in order to make the distribution density of the powder uniform in the primary and secondary classification chambers, a plurality of injection nozzles are provided, and the plurality of injection nozzles are provided at equal intervals around the outer peripheral wall of the primary classification chamber. It is good to kick. In this case, a ring-shaped powder supply header for supplying a solid-air mixed fluid is provided around the outer peripheral wall of the primary classification chamber, and a plurality of injection nozzles are connected to the powder supply header. Since almost the same amount of the solid-gas mixed fluid can be supplied to each of the injection nozzles, the powder distribution density in the primary classification chamber and the secondary classification chamber can be made more uniform.

[0015] In the airflow classifier configured as described above, when a solid-gas mixed fluid of powder and compressed air is supplied from a plurality of injection nozzles to the primary classification chamber in a state in which a suction force is applied to the fine powder discharge cylinder, The body swirls in the primary classification chamber and centrifuged into coarse powder and intermediate powder (fine powder partially containing coarse powder), and the coarse powder swirls around the outer periphery of the primary classification chamber to the coarse powder outlet. Discharged.

[0016] On the other hand, the intermediate powder moves inward of the primary classification chamber and faces the outer periphery of the secondary classification chamber. Most of them move up along the inner surface of the peripheral wall of the secondary classification chamber, and turn up radially inward along the ceiling surface of the secondary classification chamber.

At this time, a suction force is applied to the fine powder suction port, and the suction force acts on the center of the secondary classification chamber. Therefore, the intermediate powder moved radially inward along the ceiling surface is In the center of the secondary classification chamber, the flow changes downward and descends while creating a swirling vortex. The inner diameter of the descending swirling vortex is significantly smaller than the inner diameter of the secondary classification chamber, which is almost equal to the diameter of the fine powder suction port. Centrifugal separation is effective, and the coarse powder spreads outward in the radial direction, swirls and descends, flows into the primary classification chamber, is centrifuged in the primary classification chamber, and is discharged into the coarse powder discharge loca. On the other hand, the fine powder descends on the swirling vortex and is sucked and discharged together with air.

[0018] Here, if the swirl vortex formed at the center of the secondary classification chamber shifts in the radial direction of the secondary classification chamber and becomes unstable, sharp classification may not be performed. For this reason, it is preferable to provide a conical or cylindrical center core at the center of the top wall of the secondary classification chamber to stabilize the swirling vortex.

[0019] When the center core is supported so as to be movable up and down, it is easy to adjust the stability of the swirl vortex.

[0020] In the airflow classifier according to the present invention, if the height dimension of the primary classification chamber can be adjusted, or the height dimension of the secondary classification chamber can be adjusted, the classification point can be adjusted.

[0021] In addition, if the secondary classification chamber is divided into a plurality of stages in the vertical direction and the inner diameter is made smaller as it reaches the secondary classification chamber on the upper stage side, the powder in each classification chamber of the secondary classification chamber The body is classified, and as the swirl diameter of the airflow decreases and the speed increases as it reaches the secondary classification chamber on the upper stage side, an extremely high speed swirling airflow is formed only with the powder supply air. Can do. As a result, it is possible to obtain a fine powder with a very small particle size with very little coarse powder.

[0022] Furthermore, if an exhaust port is formed on the central axis of the center core, air in the secondary classification chamber can be exhausted from the exhaust port, so that the exhaust resistance is reduced, and the primary classification chamber and the secondary classification chamber are reduced. The indoor pressure can be prevented from rising abnormally, and a small blower that applies suction to the fine powder discharge cylinder or a blower that supplies high-pressure air to the powder supply cylinder can be used. [0023] In the classification plant according to the present invention, the air stream classifier, the powder supply cylinder for supplying powder to the spray nozzle of the air stream classifier, and the fine powder discharge cylinder of the air stream classifier are sent. A solid-gas separator that separates the solid-gas mixed fluid into fine powder and air; a dust collector that collects the fine powder in the air that is sent to the air-gasifier of the solid-gas separator; The dust collector is applied with a suction force, or the blower that sends compressed air to the powder supply cylinder is used.

[0024] Here, a jet mill for pulverizing powder is connected to the lower end opening of the casing of the airflow classifier, the powder outlet portion of the jet mill and the powder supply cylinder are connected by a circulation path, and the circulation is performed. When the powder supply pipe is connected in the middle of the road, the coarse powder discharged from the opening force at the lower end of the casing is crushed by the jet mill and sent again to the airflow classifier for classification, thus increasing the yield. it can.

[0025] In addition, classification processing can be performed only with high-pressure air used in a jet mill, and the entire plant can be downsized and running costs can be reduced.

[0026] In the above classification plant, the air classifier is a classifying process with a small amount of air that does not require secondary air. Therefore, the air classifier is fed from the fine powder discharge cylinder between the air classifier and the solid-gas separator. It is possible to incorporate a second airflow classifier that classifies rare powder into fine powder and ultrafine powder, which can be used as products.

The invention's effect

[0027] As described above, in the airflow classifier according to the present invention, the powder is first classified into coarse powder and intermediate powder (fine powder partially containing coarse powder) in the primary classification chamber, and then the intermediate powder is used. Since it is led to the secondary classification chamber and secondary classification is performed into coarse powder and fine powder, it is possible to enable a sharp classification process in which the coarse powder is less likely to be mixed in the fine powder.

[0028] Further, since the primary classified powder is introduced into the secondary classification chamber and classified, the powder is secondarily classified in a state where the mixing ratio of the powder and the compression air is low. The powder can be classified with extremely high accuracy.

[0029] Furthermore, since the classification process eliminates the need for secondary air, there is no turbulence in the air flow in the classification chamber, and high-precision classification is possible. In addition, since the amount of air in the classification room is small, a small blower can be used in a classification plant that uses the air classifier. At the same time, a small filter can be used as a cyclone separator for collecting fine powder and a bag filter for collecting powder in the air separated from the cyclone separator, thus reducing equipment costs and running costs. Can be achieved.

Brief Description of Drawings

FIG. 1 is a schematic view showing an embodiment of an air classifier according to the present invention.

[Figure 2] Transverse plan view of Figure 1

圆 3] Cross-sectional view showing details of upper part of air classifier

[Fig.4] Schematic diagram of classification plant using air classifier shown in Fig. 1.

[Fig.5] Schematic diagram showing another example of airflow classifier

FIG. 6 is a schematic diagram showing another example of a classification plant using the air classifier shown in FIG.

FIG. 7 is a schematic view showing another embodiment of the air classifier according to the present invention.

[8] Cross-sectional view showing details of upper part of air classifier shown in Fig. 7

圆 9] Schematic diagram of a classification plant using the air classifier shown in Fig. 7.

FIG. 10 is a schematic diagram showing another example of a classification plant using the air classifier shown in FIG.

FIG. 11 is a schematic diagram showing another example of a classification plant using the air classifier shown in FIG.

FIG. 12 is a schematic diagram showing another example of a classification plant using the air classifier shown in FIG.

[Fig. 13] Schematic diagram showing a conventional air classifier

Explanation of symbols

A

1 Airflow classifier

A

2 Airflow classifier

2 Casing

7 Classification board

8 Coarse powder outlet

11 Fine powder suction port

12 Fine powder discharge cylinder

13 Primary classification room

16 Secondary classification room

16a Upper secondary classification room 16b Lower secondary classification room

26 Center core

26c Exhaust hole

27 Conical surface

31 Powder supply header

32 Powder supply cylinder

33 Injection nozzle

40 Jet mill

62 Cyclone separator (solid-gas separator)

70 Bag filter (dust collector)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 to 3 show an air classifier A according to the present invention. This air classifier A has a casing 2. The casing 2 is divided into an upper casing 3 and a lower casing 4, and a support cylinder 5 having an internal thread formed on the inner periphery is provided on the central axis of the lower casing 4.

[0033] The support cylinder 5 is fixedly arranged, and a plurality of spacers 6 are incorporated on an inward flange 5a provided at the lower end thereof. Further, a screw cylinder 7 a provided at the center of the lower surface of the classification plate 7 is screwed into the support cylinder 5.

[0034] The height of the classification plate 7 is adjusted by increasing or decreasing the number of spacers 6 incorporated in the support cylinder 5.

[0035] The upper surface of the classification plate 7 has a conical shape inclined with an upward gradient from the outer periphery toward the center, and an annular coarse powder discharge port 8 is provided between the outer periphery and the inner periphery of the casing 2. In the embodiment, the classifying plate 7 has a conical shape, but may have a flat plate shape.

[0036] The inner peripheral upper portion of the screw cylinder 7a is a tapered hole 9, and a tapered ring 10 is detachably fitted into the tapered hole 9. The inside of the tenor ring 10 is a fine powder suction port 11. As the tenor ring 10, a tenor ring 10 having a tapered fine powder suction port 11 whose upper end is a large-diameter end is adopted here, but a tenoring having a tapered fine powder suction port whose upper end is a small-diameter end is adopted. Various diameters can be used. [0037] The upper part of the fine powder discharge cylinder 12 is connected to the support cylinder 5. Fine powder discharge cylinder 12 is L-shaped

The tip part penetrates a part of the lower casing 4 and faces the outside.

[0038] The upper casing 3 has a scat part 14 that forms a primary classification chamber 13 with the outer peripheral part of the upper surface of the classification plate 7, and a cylindrical part 15 that rises from the inner diameter part of the skirt part 14, The inside of the cylindrical portion 15 is a secondary classification chamber 16.

[0039] As the skirt portion 14, here, there is no force inclination indicating an inclination parallel to the classifying plate 7! /, And it may be a horizontal plane! /.

[0040] A plurality of spacers 17 are incorporated between the facing surfaces of the skirt portion 14 and the lower casing 4, so that the height of the primary classification chamber 13 can be adjusted by increasing or decreasing the number of the spacers 17. There is.

[0041] The cylindrical part 15 is composed of an upper ring 15a having a top wall, an intermediate ring 15b, and a lower ring 15c. The height of the classification chamber 16 can be adjusted. Instead of replacing these multiple rings, the upper wall of the secondary classification chamber 16 may be movable up and down so that the height dimension of the secondary classification chamber 16 can be adjusted. Also, as shown in FIG. 5, the secondary classifying chamber 16 may have a conical shape with a smaller diameter as it goes upward!

[0042] The upper ring 15a, the intermediate ring 15b, and the lower ring 15c are held in an assembled state in which the upper casing 3 is formed by the connecting means 20. Here, as the connecting means 20, a plurality of support pieces 21 are provided on the outer periphery of the lower casing 4, and the upper part of the screw shaft 22 whose lower end is fixed to each support piece 21 is fixed to the upper surface of the top wall of the upper ring 15a. The connecting piece 23 is passed through, and the knob 24 is screwed to the upper end portion of the screw shaft 22 and tightened.

[0043] A core insertion hole 25 is formed in the center of the top wall of the upper ring 15a, and a center core 26 is slidably inserted into the core insertion hole 25. The center core 26 has substantially the same diameter as the inner diameter of the small diameter end of the fine powder suction port 11, and a conical surface 27 is provided at the lower end. Further, a flange 28 is provided on the upper portion of the center core 26, and a height adjusting ring 29 is incorporated between the flange 28 and the top wall of the upper ring 15a. For this reason, the length of the center core 26 protruding into the secondary classification chamber 16 can be adjusted by replacing the height adjustment ring 29 with another height adjustment ring 29 having a different length. 26 to fix 26 The bolt 30 is screwed and fixed to the top wall of the upper ring 15a. The center core 26 is not limited to the illustrated example, and may be conical or cylindrical. In place of the height adjustment ring 29, the center core 26 may be configured to be continuously raised from the outside.

An annular powder supply header 31 is provided on the outer side of the joint portion between the upper casing 3 and the lower casing 4, and a powder supply cylinder 32 is connected to an outer periphery facing position of the powder supply header 31.

A plurality of injection nozzles 33 are provided at equal intervals on the inner periphery of the powder supply header 31.

Each injection nozzle 33 is configured to inject a solid-gas mixed fluid of powder and compressed air supplied into the powder supply header 31 toward the outer circumferential portion in the primary classification chamber 13.

FIG. 4 shows a classification plant that employs the air classifier A configured as described above. In this classification plant, a powder supply device 50 is connected to the powder supply cylinder 32 of the airflow classifier A. The powder supply device 50 sucks the powder stored in the hopper 53 by compressed air injected from the air injection nozzle 51 into the powder supply pipe 52, passes through the powder supply pipe 52, and passes through the powder supply pipe 52. Send it to 32.

[0047] The fine powder classified by the airflow classifier A and sucked and discharged into the fine powder discharge cylinder 12 is sent from the fine powder supply path 61 to a cyclone separator 62 as a solid-gas separator.

[0048] The cyclone separator 62 separates fine powder and air. The product fine powder is also discharged at the outlet 63 at the lower end, and air is sent from the air supply path 64 to the bag filter 70 as a dust collector.

[0049] The nog filter 70 collects powder contained in the air. Clean air is blower

It is sucked by 72 and discharged to the outside.

[0050] Now, in a state where the blower 72 is operated and a suction force is applied to the fine powder discharge cylinder 12, a solid-gas mixed fluid of powder and compressed air is applied to the powder supply cylinder 32 of the airflow classifier A shown in FIG. When supplied, the solid-gas mixed fluid is jetted from the plurality of jet nozzles 33 toward the outer periphery of the primary classification chamber 13.

[0051] At this time, since the plurality of spray nozzles 33 are provided at equal intervals, the solid-gas mixture to be classified is classified. The combined fluid is supplied into the primary classification chamber 13 in a uniform state, swirled at a high speed in the primary classification chamber 13 and centrifuged into coarse powder and intermediate powder, and the coarse powder is separated into the primary classification chamber 13. It turns around the inner periphery and is discharged from the coarse powder outlet 8.

[0052] On the other hand, when the intermediate powder moved inward of the primary classification chamber 13 moves to a position facing the outer peripheral portion of the secondary classification chamber 16, most of the intermediate powder moves along the inner surface of the peripheral wall of the secondary classification chamber 16. Move upward while turning. On the other hand, a part of the fine powder moves to the center of the casing 2 and is sucked into the fine powder suction port 11.

[0053] The intermediate powder rising while swirling around the outer periphery of the secondary classification chamber 16 changes its direction radially inward along the ceiling surface of the secondary classification chamber 16.

[0054] Here, if the intersection between the inner peripheral surface of the secondary classification chamber 16 and the ceiling surface is angular, the direction change lacks smoothness, and powder adheres to and accumulates at the intersection. It is preferable to round off the crossing because there is a possibility that the peeled material may be mixed.

The intermediate powder that has moved inward in the radial direction along the ceiling surface of the secondary classification chamber 16 changes its flow downward along the outer periphery of the center core 26. At this time, since the suction force of the blower 72 is acting on the fine powder suction port 11, the intermediate powder whose flow has been changed downward moves downward while forming a swirling vortex. The inner diameter of this swirling vortex is a small diameter that is almost equal to the minimum inner diameter of the fine powder suction port 11, and is much smaller than the swirling vortex diameter at the time of ascent. And effectively centrifuged.

[0056] The separated coarse powder swirls and descends while spreading outward in the radial direction, reflows into the primary classification chamber 13, and is centrifuged again on the swirl flow in the primary classification chamber 13 to the outer periphery. It moves and is discharged from the coarse powder outlet 8.

On the other hand, the fine powder descends along the swirl vortex, or descends along the cavity formed at the center of the swirl vortex and is sucked into the fine powder suction port 11.

In this way, the powder is centrifuged in the primary classification chamber 13 to be primary classified into coarse powder and intermediate powder, and the intermediate powder is then centrifuged in the secondary classification chamber 16. Since it is secondarily classified into coarse powder and fine powder again, it is possible to achieve a sharp classification process that almost eliminates the presence of coarse powder in the fine powder.

[0059] In addition, the intermediate powder flowing into the secondary classification chamber 16 is primarily classified to remove most of the coarse powder. Therefore, the swirl vortex formed in the center of the secondary classification chamber 16 is a swirl vortex with a small inner diameter, and the swirl speed is high. It can be classified with great precision.

[0060] Furthermore, by making the shape of the secondary classification chamber 16 conical as shown in FIG. 5, the swirling speed of the intermediate powder in the secondary classification chamber 16 increases as it goes upward, and the classification accuracy is further increased. I can give you.

[0061] In addition, since the powder is classified only by the compressed air of the solid-gas mixed fluid supplied to the powder supply cylinder 32, the airflow is not disturbed and high-precision classification can be performed. In addition, the air volume is small, and a small blower 72 can be used. In addition, the cyclone separator 62 for collecting fine powder and the bag filter 70 for collecting powder in the air can be used in a small size, thereby reducing the size of the device and reducing the equipment cost and running cost. be able to.

[0062] As shown in the embodiment, the flow velocity of the swirling flow can be adjusted by changing the height dimension of the primary classification chamber 13 or the height dimension and inner diameter of the secondary classification chamber. Can be adjusted. Furthermore, the classification point can also be adjusted by changing the inner diameter of the fine powder suction port 11.

Further, by providing the center core 26, a stable swirl vortex can be formed. Further, by changing the number of the injection nozzles 33 or the cross-sectional area of the injection nozzles 33, the swirling speed and dispersion state of the solid-gas mixed fluid supplied to the primary classification chamber 13 can be adjusted.

[0064] In Fig. 4, a force that applies a suction force to the air classifier A by the blower 72. Compressed air is sent from the blower 73 indicated by the chain line in the figure into the powder supply cylinder 32 to cause the powder to flow. You may push into the classifier A and blow air.

FIG. 6 shows another example of a classification plant. In this example, coarse powder discharged from the lower end outlet 34 of the casing 2 of the airflow classifier A is supplied into the hopper 41 of the jet mill 40.

[0066] The jet mill 40 guides the coarse powder supplied into the hopper 41 by compressed air injected from the air injection nozzle 42 into a crushing chamber (not shown), and the collision provided in the crushing chamber Since the conventional force of crushing by colliding with the plate is well known, the details are not shown.

[0067] The powder pulverized by the jet mill 40 is fed into the powder supply cylinder 32 from the circulation path 43 together with the high-pressure air. A powder supply device 50 is connected in the middle of the circulation path 43. The powder supply device 50 sucks the powder stored in the hopper 53 by the compressed air injected into the powder supply pipe 52 from the air injection nozzle 51 into the powder supply pipe 52 and enters the circulation path 43. I am trying to send it in.

[0068] As shown in FIG. 6, the coarse powder discharged from the airflow classifier A force is pulverized by the jet mill 40, and the pulverized powder is supplied to the powder supply cylinder 32 and circulated. Yield can be improved. In addition, since the air classifier A does not require the introduction of secondary air, the entire classification plant can be operated with a smaller amount of air than before, and the blower can be omitted.

FIG. 7 and FIG. 8 show another embodiment of the air classifier according to the present invention. In the airflow classifier A in this embodiment, the secondary classification chamber 16 is vertically arranged in two stages.

2

The upper secondary classification chamber 16a has an inner diameter smaller than the inner diameter of the lower secondary classification chamber 16b.

[0070] Further, the center core 26 is formed by the outer core 26a and the inner core 26b inserted into the outer core 26a and adjustable in height by the height adjusting ring 29, and the exhaust hole 26c is formed on the central axis of the inner core 26b. Establish

Further, the tenor ring 10 having a tapered fine powder suction port 11 whose upper end is a small diameter end is used. Since the other configuration is the same as that of the air classifier shown in FIG. 3, the same parts are denoted by the same reference numerals and description thereof is omitted.

FIG. 9 shows a classification plant using the airflow classifier A shown in FIGS. 7 and 8. This minute

2

In the class plant, as in the class plant shown in FIG. 6, the hopper 41 of the jet mill 40 is connected to the lower end outlet of the casing 2, and the classified coarse powder is pulverized by the jet mill 40. The powder after the treatment is sent from the circulation path 43 into the primary classification chamber 13. Since other configurations are the same as those in FIG. 6, the same components are denoted by the same reference numerals and description thereof is omitted. [0073] As described above, the secondary classification chamber 16 of the airflow classifier A is divided into the upper secondary classification chamber 16a and the lower classification side.

2

The powder is classified in the secondary classification chamber 16b, and is classified in the lower secondary classification chamber 16b by making the inner diameter of the upper secondary classification chamber 16a smaller than the inner diameter of the lower secondary classification chamber 16b. Can be classified again in the upper secondary classification chamber 16a, and the swirl diameter of the airflow decreases and the speed increases as it reaches the upper secondary classification chamber 16a. A clean whirling air flow of extremely high speed can be formed with only air for body supply. As a result, it is possible to obtain a fine powder having a very small particle diameter and containing very little coarse powder.

[0074] When the exhaust hole 26c is formed on the central axis of the inner core 26b forming the center core 26, a part of the air in the secondary classification chamber 16 is exhausted from the exhaust hole 26c, and the exhaust resistance is low. Therefore, the pressure in the primary classification chamber 13 and the secondary classification chamber 16 can be prevented from rising abnormally, and a small blower 72 that applies suction to the fine powder discharge cylinder 12 should be used. Can do. In addition, by providing the damper D above the exhaust hole 26c, the particle size can be changed by adjusting the opening of the damper D and adjusting the exhaust amount.

[0075] In Figs. 7 and 8, the secondary classification chamber 16 is divided into two stages in the vertical direction, but the number of divisions is not limited to this. For example, it may be divided into three or more stages. In addition, the upper secondary classification chamber 16a of the secondary classification chamber 16 has a cylindrical shape, but as in the case of FIG. 5, it may have a conical shape with a smaller diameter toward the upper end.

FIG. 10 to FIG. 12 show other classification plants using the air classifier A shown in FIG. 7 and FIG.

2

An example of The classification plant shown in Fig. 10 is used when high classification accuracy is required or in the case of multi-product classification, and the second between the air classifier A and the cyclone separator 62.

2

The airflow classifier A is installed, and the fine powder classified by the airflow classifier A is

twenty two

2 is supplied to the powder supply cylinder 32 of the air classifier A, and the powder is classified again, and the

2

The product is the fine powder extracted by opening valve B attached to the bottom outlet of Sing 2.

[0077] Further, the ultrafine powder discharged from the fine powder discharge cylinder 12 of the second airflow classifier A is divided into cyclones.

2

It is sent to the release machine 62 and separated into powder and air. Since the other configuration is the same as that of the classification brand shown in FIG. 9, the same parts are denoted by the same reference numerals and the description thereof is omitted. [0078] Like the classification plant described above, the second air is provided between the air classifier A and the cyclone separator 62.

2

By incorporating the flow classifier A, a fine powder with a small particle size distribution width can be obtained.

2

wear.

The classification plant shown in FIG. 11 has a configuration in which the jet mill 40 of the classification plant shown in FIG. 9 is omitted. In the classifying plant shown in this example, suction force is applied to the air classifier A by the operation of the blower 72, and the suction force and the powder supply cylinder 32 are fed.

2

Force that causes the powder to be guided into the air classifier A by air Blower shown by the chain line in the figure

2

Compressed air is fed into the powder supply cylinder 32 from 73 and the powder is pushed into the airflow classifier A.

2

You may blow. In this case, the blower 72 is not necessary.

[0080] In the classification plant shown in FIG. 12, the air classifier A of the classification plant shown in FIG.

2 A second airflow classifier A is installed between the cyclone separators 62 and the second airflow classifier A

2 2 As a product, the fine powder that is also discharged from the lower end outlet force of the casing 2 is used.

In the classification plant shown in FIG. 12, the blower 72 shown in FIG. 12 may be used to push the powder into the airflow classifier A and blow air without providing the blower 72. Also with blower 72

2

Blower 73 may be used in combination.

Claims

The scope of the claims

[1] A classification plate is provided in the casing, and a substantially cylindrical primary classification chamber is provided on the outer periphery of the upper surface of the classification plate in the casing, and is substantially smaller in diameter than the primary classification chamber on the same axis as the primary classification chamber. A cylindrical or conical secondary classification chamber is formed, and a solid-gas mixed fluid of powder and compressed air is sprayed on the peripheral wall of the primary classification chamber in the circumferential direction of the outer periphery of the primary classification chamber An air classifier in which a nozzle is provided, a coarse powder discharge port is formed between the outer periphery of the classification plate and the inner peripheral surface of the casing, and a fine powder discharge tube is connected to a fine powder suction port formed in the center of the classification plate.

[2] The airflow classifier according to claim 1, wherein a plurality of the injection nozzles are provided, and the plurality of injection nozzles are provided at equal intervals around the outer peripheral wall of the primary classification chamber.

[3] A ring-shaped powder supply header for supplying a solid-air mixed fluid is provided around the outer peripheral wall of the primary classification chamber, and the plurality of injection nozzles are connected to the powder supply header to each injection nozzle. The air classifier according to claim 2, wherein a solid-gas mixed fluid is supplied.

[4] The conical or cylindrical center core is provided at the center of the top wall of the secondary classification chamber.

The air classifier according to any one of 1 to 3.

5. The air classifier according to claim 4, wherein the center core is supported so as to be movable up and down.

6. The air classifier according to any one of claims 1 to 5, wherein a height dimension of the primary classification chamber can be adjusted.

[7] The airflow classifier according to any one of [1] to [6], wherein a height dimension of the secondary classification chamber is adjustable.

[8] The air flow classifier according to any one of claims 1 to 7, wherein the secondary classification chamber is divided into a plurality of stages in the vertical direction, and the inner diameter is made smaller as it reaches the upper secondary classification chamber. .

[9] The airflow classifier according to any one of claims 4 to 8, wherein an exhaust port is formed on a central axis of the center core.

[10] The airflow classifier according to any one of claims 1 to 9, a powder supply cylinder that supplies powder to an injection nozzle of the airflow classifier, and a fine powder discharge cylinder of the airflow classifier A solid-gas separator that separates the solid-air mixed fluid into fine powder and air, a dust collector that collects the fine powder in the air fed from the air outlet of the solid-gas separator and clarifies the air, The dust collector A classification plant comprising a blower that applies a suction force to the powder supply or feeds compressed air into the powder supply cylinder.

[11] A jet mill for pulverizing powder is connected to the lower end opening of the casing of the air classifier, and the powder outlet portion of the jet mill and the powder supply cylinder are connected by a circulation path. The classification plant according to claim 10, wherein a powder supply pipe is connected in the middle.

[12] A claim in which a second air classifier is installed between the air classifier and the solid-gas separator to classify the fine powder fed from the fine powder discharge cylinder into a fine powder and a super fine powder. Item 12. Classification plant according to item 10 or 11.