JP2011189225A - Classifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a classifier for classification capable of removing fine powder of a raw powder without deterioration of productivity. <P>SOLUTION: In a casing of the classifier having a raw material supply port in the upper part and a coarse powder discharge port in the lower part, provided are a classifying rotor having two or more classifying blades rotating about a rotation shaft and a guide blade ring consisting of two or more guide blades communicating with a gas introduction inlet at specified intervals on the outer peripheral surface of the classifying rotor. Fine powder, together with a gas supplied through the guide blade ring, is made to flow into the classifying rotor, and coarse powder is made to flow into a coarse powder storage chamber arranged below the guide blade ring and discharged. The dispersed state of the powder is improved by attaching a deflector to the inner peripheral surface of the guide blade ring because of impingement of the powder to the deflector. When the tip of the deflector approaches the classifying rotor, the powder is guided to the vicinity of the classifying rotor by the deflector, making fine powder in the powder flow easily into the classifying rotor and thus improving the classification precision. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a classifier that separates powder into fine powder and coarse powder, and more specifically, removes fine powder smaller than a predetermined particle size to obtain a product having a predetermined particle size range. .

  Conventionally, as a classification means for classifying powder into fine powder and coarse powder, a centrifugal force is applied to the powder by a cylindrical classification rotor rotating around a central axis extending in the vertical direction, and formed around the classification rotor. While supplying the raw material powder to the annular space, the gas flows from the outside in the radial direction of the classification rotor to the inside, and only the fine powder is transported into the classification rotor together with the gas, and the coarse powder is discharged from the lower discharge port for separation. Such vertical axis classifiers are used in the field of manufacturing toners, powder coatings, and the like. For example, in the toner manufacturing process, in recent years, in order to realize high-speed printing and high resolution, a toner having an average particle diameter of 5 μm to 7 μm and no fine powder of 4 μm or less is required.

In such classification, in order to remove fine powder efficiently, the dispersion of the raw material powder in the classifier is strengthened, and the residence time of the powder swirling around the classification rotor by increasing or decreasing the residence time Optimal adjustment of the amount is an effective method.
As such a classifier, for example, a classifier described in Patent Document 1 that makes assembly and disassembly easy by making the classification rotor and the drive shaft removable, and the dispersion state of the powder in the annular space is classified accuracy. And the product yield, the tandem classifier described in Patent Document 2 has improved dispersibility in the annular space by providing a plurality of classification rotors having the same rotation axis direction in one casing. Is also known. Further, in the classifiers of Patent Documents 1 and 2, described in Patent Document 3 in which discharge vanes that rotate integrally with the classification rotor are provided in the coarse powder storage chamber for the purpose of preventing the powder from adhering to the coarse powder discharge port. A classifier has also been reported.

  In Patent Documents 1 to 3, in order to improve dispersibility, a plurality of guide vanes communicating with the gas inlet are provided outside the outer peripheral surface of the classification rotor with a slit-shaped gap, and this slit-shaped By flowing gas into the classification chamber from the gap, the raw material powder around the classification rotor is dispersed. There has also been reported an apparatus that adjusts the residence time of the raw material powder by providing a spiral member on the inner peripheral portion of the guide vane and reliably discharging the raw material powder along the spiral member. Furthermore, by blowing gas (hereinafter referred to as rinsing air) from the gap between the classification rotor and the casing, powder (coarse powder) of a predetermined size or more is prevented from being mixed into the fine powder from the gap, It has also been reported that the dispersibility can be improved and the residence time can be adjusted by ejecting the gas.

  However, also in the classifier, when the amount of raw material powder charged from the raw material inlet increases, the mixing of fine powder of 4 μm or less into the coarse powder (product) increases. On the other hand, when the rotational speed of the classification rotor is reduced to reduce the fine powder of 4 μm or less into the coarse powder (product), the product having a particle size that should be the product is discharged together with the fine powder. , The coarse powder (product) yield will decrease. Thus, in either case, productivity was not sufficient.

JP-A-11-216425

JP 2000-157934 A

Utility Model Registration No. 3153873

  In view of the above problems, an object of the present invention is to provide a classifier that can prevent the mixing of fine powder into coarse powder (product) without reducing productivity.

  A first feature of the present invention is that a classification rotor having a plurality of classification blades rotating around a rotation axis in a casing having a raw material supply port at an upper portion and a coarse powder discharge port at a lower portion, and an outer peripheral surface of the classification rotor And a guide vane ring composed of a plurality of guide vanes communicating with the gas inlet at a predetermined interval, and fine powder flows into the classification rotor together with the gas supplied through the guide vane ring, and coarse powder is introduced into the guide vanes. In the classifier configured to flow into and discharge from a coarse powder storage chamber provided below the ring, a deflection plate is attached to the inner peripheral surface of the guide blade ring, and the tip of the deflection plate is positioned more than the tip of the guide blade. It is attached close to the classification rotor.

  By attaching the deflection plate to the inner peripheral surface of the guide blade ring, the powder swirling in the classification chamber collides with the deflection plate. As a result, the powder is loosened and the dispersibility of each particle is improved. Further, the powder swirls along the deflection plate. At that time, the tip of the deflecting plate is brought close to the classifying rotor, so that the powder is guided to the vicinity of the classifying rotor by the deflecting plate, and collides with the classifying blade near the classifying rotor to be dispersed and perform the classifying action. receive. Thus, the fine powder in the powder easily flows into the classification rotor, so that the classification accuracy is improved.

  According to a second aspect of the present invention, the deflection plate is attached to a tip end portion of the guide blade on the rotational direction side of the classification rotor with respect to the guide blade ring.

  By attaching the deflection plate to the guide blade ring at the tip of the guide blade on the rotational direction side of the classification rotor, the powder colliding with the deflection plate by the classification air flowing in from the gap between the adjacent guide blades In addition, the swirling airflow is not forcibly pushed by the classifying rotor, and is also moderately attracted, so that dispersion and classification are effectively imparted.

  A third feature of the present invention resides in that, instead of attaching the deflecting plate to the inner peripheral surface of the guide blade ring, it is attached to a spiral member disposed in an annular space between the guide blade ring and the classification rotor. is there.

  By providing the deflection plate on the spiral member, the powder can be classified reliably and the classification accuracy can be improved. That is, the powder descending along the spiral member surely collides with the deflecting plate, and as a result, the aggregation is loosened and dispersed. And since a powder is guide | induced to the classification rotor vicinity along a deflection | deviation plate and receives a classification effect | action, classification accuracy improves.

  The fourth feature of the present invention is that the deflecting plate is inclined 20 degrees to 70 degrees in the classifying rotor rotation direction side with respect to the classifying rotor center, and a gap between the tip of the deflecting plate and the outer peripheral surface of the classifying rotor is formed. It is characterized by being 3 mm to 12 mm.

By setting the inclination angle of the deflecting plate to 20 to 70 degrees toward the classifying rotor rotation direction with respect to the classifying rotor center, the powder collides with the deflecting plate and approaches the classifying rotor along the deflecting plate. Therefore, the collision with the classification rotor causes both dispersion and classification, so that the classification accuracy is improved.
In addition, by setting the clearance between the tip of the deflection plate and the outer peripheral surface of the classifying rotor to 3 mm to 12 mm, the space (classification chamber) between the inner peripheral surface of the guide blade ring and the outer peripheral surface of the classifying rotor is carried on the swirling airflow. During the swiveling, the powder is repeatedly collided between the deflection plate and the classification blade. Thereby, the aggregation of the powder is loosened, the dispersibility is improved, and only the fine powder can be efficiently removed.

A fifth feature of the present invention resides in that the deflection plate is provided for a classifier in which a plurality of the classifying rotors are coaxially connected.

By connecting a plurality of classification rotors on the same axis, the powder classification region can be extended, the dispersibility of the deflecting plate can be improved, and the classification accuracy can be improved.

Longitudinal sectional view of the classifier of the first embodiment Cross section of guide vane ring with deflection plate Perspective view of helical member with deflection plate Vertical section of the classifier of the second embodiment

(First embodiment)
The classifier of the present invention will be described with reference to FIGS. The classifier includes a cylindrical classification rotor 2 housed in an upper portion of a casing 1, a discharge rotor 4 that is coaxially coupled to the classification rotor 2, and a classification rotor 2 that pivotally supports the discharge rotor 4. A drive shaft 3 for rotating the discharge rotor 4 is also provided. The classification rotor 2 includes a classification rotor 2 and a guide blade ring 5 having a plurality of guide blades 5a arranged in an annular shape at intervals.

  The classifying rotor 2 includes an upper disk 6, a lower disk 7 that is vertically spaced from the upper disk 6, and a space between the upper disk 6 and the lower disk 7. The plurality of classification blades 8 are connected and radially arranged on the outer peripheral side of the discs 6 and 7.

  A plurality of dispersing blades 9 are provided on the outer peripheral side of the upper surface of the upper disk 6 so that the powder supplied from the raw material supply port 13 provided on the upper surface of the casing 1 is dispersed and uniformly distributed over the entire periphery. Is formed.

  The classifying blades 8 are radially arranged along the outer peripheral surface of the classifying rotor 2 at equal intervals, and the shape and direction of the cross section thereof can be arbitrarily selected from known classifying blades, and two adjacent to each other. The slit-shaped gap formed between the two classification blades 8 is designed to have a shape suitable for the gas flow.

  The discharge rotor 4 includes an annular top plate 10 having the same opening as that of the lower disk 7, a circular bottom plate 11 disposed below the top plate 10 at an interval, and a space between the top plate 10 and the bottom plate 11. A plurality of blades 12 that are connected to each other are arranged radially at equal intervals by providing a distance between adjacent blades 12. A drive shaft 3 is connected to the bottom plate 11 to rotatably support the discharge rotor 4 and the classification rotor 2. The discharge rotor 4 also functions as a member that rotatably supports the classifying rotor 2, and the blade 12 is composed of a material, width, thickness, length, etc. that has sufficient strength as a support member. ing.

Here, the classification rotor 2 and the discharge rotor 4 are communicated with each other through an opening 14 formed in the lower disk 7 of the classification rotor 2. By making the diameter of the opening 14 smaller than the inner diameter of the discharge rotor 4, it becomes difficult for the gas in the classification rotor 2 to flow into the discharge rotor 4, and the flow of the gas to flow into the classification rotor 2 is suppressed. This makes it difficult for coarse powder to enter the classification rotor 2. Further, by reducing the diameter of the opening 14, the gas flowing into the discharge rotor 4 is accelerated, and the discharge of fine powder in the discharge rotor 4 is also promoted.

  The guide blade rings 5 are arranged at equal intervals along the circumferential direction of the outer peripheral surface of the classification rotor 2 in a state in which the blades of the plurality of guide blades 5a extend in the vertical direction, and the direction of the gap between the guide blades 5a is, for example, In order to enhance the dispersion effect on the powder that swirls and flows in the classification chamber 15, it is arranged in a tangential direction toward the outer peripheral surface of the classification rotor 2 as shown in FIG. 2.

  A gas introduction chamber 17 for supplying classification air to the classification chamber 15 through the guide blade ring 5 is provided on the outer periphery of the guide blade ring 5. The gas introduction chamber 17 is formed coaxially with the guide vane ring 5 in the casing 1 outside the guide vane ring 5, and a gas introduction port 20 is provided in the gas introduction chamber 17.

The number of guide blades 5a in the guide blade ring 5 is eight in FIG. 2, but the number of guide blades is not limited to this. In other words, by appropriately changing the number of guide blades 5a, the blade shape, and the gap between the blades, the passage speed of the air passing through the gap can be changed, and as a result, the dispersibility of the powder during classification is improved. can do.

The guide vane 5 has four deflecting plates 28 inclined to the guide vane 5a by about 20 to 70 degrees with respect to the center O of the classifying rotor 2 in the rotation direction of the classifying rotor 2, and the tip of the deflecting plate 28. And the classifying rotor 2 are arranged and attached so that the clearance between them is 3 to 12 mm. By attaching the deflecting plate 28 to the guide blade ring 5, the powder swirling in the classification chamber 15 collides with the deflecting plate 28. As a result, aggregation is loosened and dispersibility is improved. The powder flows along the deflection plate 28 together with the swirling airflow. At this time, the tip of the deflection plate 28 is brought close to the classification rotor 2, whereby the powder is guided to the vicinity of the classification rotor 2 by the deflection plate 28 and collides with the classification blade 8 in the vicinity of the classification rotor 2. Dispersed and classified. In this way, the fine powder in the powder easily flows into the classification rotor 2, so that the classification accuracy is improved.

Here, the deflection plate 28 is attached to the tip end portion of the guide blade 5a on the rotational direction side of the classification rotor 2. This position is adjacent to the gap between the adjacent guide blades 5a. Since this gap serves as an inlet for classifying air, a deflecting plate 28 is disposed in front of the gap, so that the powder or swirling airflow that collides with the deflecting plate 28 by the classifying air is forced to the classifying rotor 2. The dispersion and classification are effectively imparted without being carried out and receiving an appropriate attracting action.

  By the way, the mounting position, the inclination angle, the size, the number, etc. of the deflection plate 28 are not limited to this. For example, the deflection plate 28 may be attached without being inclined toward the center of the classifying rotor 2 (inclination angle 0 degree). In this case, the deflection plate itself is made smaller or the height is lowered. It is possible. That is, even with the deflecting plate 28 having such a shape, the airflow and the powder swirling along the inner surface of the guide blade ring 5 in the classification chamber 15 are not sufficient for collision and dispersion. It can be a thing. Therefore, the length of the deflecting plate 28 needs to be at least about 5 mm from the inner surface of the guide blade ring 5. However, if the deflection plate 28 is too large, the distance from the classifying rotor 2 is narrowed, and the classifying effect is affected. Therefore, as a result of considering the gap between the outer peripheral surface of the classifying rotor 2 and the inner peripheral surface of the guide blade ring 5 as the gap between the deflection plate 28 and the outer peripheral surface of the classifying rotor 2, it is considered that 3 to 12 mm is appropriate. Further, the shape of the deflection plate 28 is not limited to a flat plate shape, and may be bent or curved.

Thus, by appropriately selecting the attachment position, inclination angle, size, number, and shape of the blades 28, it is possible to adjust the amount of powder that swirls in the vicinity of the classification rotor, and as a result, fine powder to be removed. Can be effectively classified and removed.
For example, as another embodiment, it is possible to give the same function as that of the deflecting plate 28 by extending the tip portion of a part of the plurality of guide blades 5a and bending the extended portion inward. is there.

  Further, as a means for more efficiently removing fine powder swirling in the vicinity of the classification rotor 2, a strip-shaped member provided with the deflection plate 28 in an annular space between the inner peripheral surface of the guide blade ring 5 and the outer peripheral surface of the classification rotor 2. It is also effective to attach to the spiral member 16 made of 29.

That is, the annular space between the inner peripheral surface of the guide blade ring 5 and the outer peripheral surface of the classifying rotor 2 is an area for sorting the raw material powder into fine powder and coarse powder as the classification chamber 15, and classification is performed in this annular space. A spiral member 16 for adjusting the residence time of the powder in the chamber 15 is arranged coaxially with the classification rotor 2. The spiral member 16 is a belt-like member formed in a spiral shape, is fixed to the inner peripheral portion of the guide blade ring 5, and extends over almost the entire length of the classification chamber 15 in the height direction. A minute gap is formed between the inner peripheral surface of the spiral member 16 and the outer peripheral surface of the classifying rotor 2 so as not to contact.

By selecting the gradient of the spiral member 16, the residence time of the powder can be adjusted effectively. That is, increasing the gradient shortens the residence time, and decreasing the gradient increases the residence time.

The spiral member 16 may be composed of a plurality of strip-shaped members. In this case, the plurality of the spiral members 16 are attached to the inner peripheral surface of the guide blade ring 5 so as to be spiraled over the entire circumference by attaching the plurality of the members in a circumferential direction. The shaped member 16 can be attached, and the choice for forming a desired gradient can be expanded.
The spiral member 16 does not necessarily extend over the entire length in the height direction of the classification blade 8, and may be provided only in a partial partition region in the height direction of the classification blade 8. Alternatively, the spiral member 16 may be attached to the guide blade ring 5 and integrated.

The deflection plate 28 is attached to the spiral member 16 between the belt-like members 29. That is, it is easier to manufacture the deflecting plate 28 to the spiral member 16 than the deflecting plate 28 is attached to the guide blade 5a, and it is advantageous in terms of strength. In addition, as shown in FIG. 3, in the present embodiment, four deflecting plates 28 are attached between the belt-like members 29, but the present invention is not limited to this.

The deflecting plate 28 is formed of a flat plate-like member, and is uniformly disposed in the spiral member 16 and is attached to the center O of the classifying rotor 2 at an angle of about 40 degrees toward the classifying rotor rotation direction in FIG. It has been. By attaching the deflection plate 28 to the spiral member 16, the powder descends along the belt-like member 29 of the spiral member 16 and collides with the deflection plate 28. As a result, the agglomeration of the powders is loosened and dispersed, and the powders travel toward the vicinity of the classification rotor along the deflection plate 28. Then, it collides with the classification blade 8 of the classification rotor 2 and receives both actions of dispersion and classification, so that fine powder in the powder flows into the classification rotor 2 and is removed, thereby improving the classification accuracy.

  As for the attachment of the deflection plate 28 to the spiral member 16, when the spiral member 16 is attached to the inside of the guide blade ring 5, the deflection plate 28 is on the rotation direction side of the classification rotor 2 of the guide blade 5a. It arrange | positions so that it may become a position corresponding to the front-end | tip part. Further, it is important that the deflection plate 28 and the guide blade 5a are in close contact with each other so that a slight gap does not occur. If there is a gap in the portion, the raw material powder may be clogged or the flow of the swirling airflow may be changed, and the function of the deflecting plate 28 may not be sufficiently exhibited.

Inside the casing 1, a passage for discharging fine powder and coarse powder selected by the classification rotor 2 is formed. The fine powder is discharged to an annular fine powder storage chamber 18 provided on the outer periphery of the discharge rotor 4 below the classification rotor 2 and then discharged from a fine powder discharge port 21 attached to the fine powder storage chamber 18. The coarse powder is discharged to an annular coarse powder storage chamber 19 disposed in communication with the lower portion of the classification chamber 15 and then discharged from a coarse powder discharge port 22 attached to the coarse powder storage chamber 19. The

A seal portion 23 is provided between the lower surface of the lower disk 7 and the casing 1. By sending pressurized gas from the passage 26 to the seal portion 23, the fine powder storage chamber 18 and the coarse powder storage chamber 19 are air-sealed so as to prevent leakage of coarse powder or fine powder. Yes. This pressurized gas is called rinsing air, and flows out from the seal portion 23 to the fine powder storage chamber 18 and the coarse powder storage chamber 19, respectively.

The fine powder storage chamber 18 is provided in the outer peripheral space of the discharge rotor 4 disposed at the lower portion of the classification rotor 2, and through the gap between the blades 12 of the discharge rotor 4 and the opening 14 provided in the lower disk 7 of the classification rotor 2. It communicates with the inside of the classification rotor 2. A fine powder discharge port 21 for discharging fine powder to the outside of the classifier is attached to the fine powder storage chamber 18.

The coarse powder storage chamber 19 is located below the classification chamber 15 and is provided in communication with the classification chamber 15. The coarse powder storage chamber 19 is provided with a coarse powder discharge port 22 for discharging the coarse powder to the outside of the classifier.

Inside the coarse powder storage chamber 19, an annular disk 24 having an L-shaped cross section called a centrifugal ring is provided. The annular disk 24 is formed in a shape along the inner side surface and the bottom surface of the coarse powder storage chamber 19, and the upper end thereof is attached to the lower disk 7 of the classification rotor 2 and rotates integrally with the classification rotor 2. .

A plurality of discharge vanes 25 are arranged on the upper surface of the annular disk 24 along the outer periphery. By rotating the discharge blade 25 integrally with the classifying rotor 2, a strong centrifugal force can be applied to the coarse powder in the coarse powder storage chamber 19, and clogging and staying around the coarse powder discharge port 22 can be prevented. The coarse powder can be quickly discharged out of the classifier.

The gap between the annular disk 24 and the inner side surface and bottom surface of the coarse powder storage chamber 19 serves as a passage for rinsing air. Thus, the rinsing air that enters the coarse powder storage chamber 19 from the passage 26 flows out into the coarse powder storage chamber 19 through the inner side surface and bottom surface of the coarse powder storage chamber 19 and the passage below the annular disk 24. Thus, the coarse powder in the coarse powder storage chamber 19 is fluidized by being rolled up by the outflow of rinsing air when pushed out in the centrifugal direction by the annular disk 24, and the coarse powder is effectively suppressed from agglomerating and adhering. The discharge from the powder storage chamber 19 is performed smoothly. In addition, by pulverization of the agglomerates and separation of the fine powder and coarse powder mixed in the coarse powder by fluidization, mixing of the fine powder into the coarse powder can be prevented and an effect of improving classification accuracy can be expected.

In the above configuration, gas is supplied to the gas introduction chamber 17 from the gas introduction port 20, and this gas is ejected to the classification chamber 15 through the gap between the guide blades 5 a and through the gap formed in the classification blade 8. It flows into the rotating classification rotor 2. Here, the raw material powder supplied from the raw material supply port 13 is dispersed in the entire circumferential direction by the upper disk 6 of the classification rotor 2 and fed into the classification chamber 15. The raw material powder is classified and classified into fine powder and coarse powder in the classification chamber 15.

Then, a powder having a small particle diameter that can pass through the classification rotor 2 in the classification chamber 15, that is, fine powder, rides on the gas flow and flows into the classification rotor 2. 7 flows into the discharge rotor 4 from the opening 14, and then is discharged from the discharge rotor 4 through the fine powder storage chamber 18 through the fine powder discharge port 21 and collected by a collector such as a bag filter or a cyclone (not shown).

On the other hand, a powder having a large particle diameter that cannot pass through the classification rotor 2 by riding on the gas flow, that is, coarse powder descends along the spiral member 16 in the classification chamber 15 and is received by the coarse powder storage chamber 19. In the coarse powder storage chamber 19, the coarse powder is fluidized by the annular disk 24 and the rinsing air, applied with centrifugal force by the discharge vanes 25, discharged to the outside from the coarse powder discharge port 22 and collected.

(Second embodiment)
The classifier shown in FIG. 4 has a configuration in which a classifier similar to the classifier according to the first embodiment is symmetrically combined upside down on the same axis. That is, the guide blade ring 5 and the spiral member 16 are the same as those in the above embodiment, and a plurality of the deflection plates 28 are attached to the spiral member 16.

The classifier comprises a pivotable casing that opens up and down via a hinge 30. This casing has an upper casing 1a and a lower casing 1b, and accommodates classification rotors 2a and 2b, respectively. The figure shows a state in which both casings 1a and 1b are closed.

The lower casing 1b and the classification rotor 2b are the same as those of the first embodiment described above, and the upper casing 1a and the classification rotor 2a are obtained by vertically inverting the lower casing 1b and the classification rotor 2b. They are arranged symmetrically on the same axis.

The classification rotor 2a is driven by a drive motor 31a, and this drive motor 31a is connected to the classification rotor 2a via a drive shaft 3a. Similarly, the classification rotor 1b in the lower casing 1b is driven by a drive motor 31b, and this drive motor 31b is connected to the classification rotor 2b via a drive shaft 3b.

The classification rotors 2a and 2b are supported in a cantilever manner, and the drive shafts 3a and 3b and the fine powder storage chambers 18a and 18b are arranged symmetrically.
A raw material supply port 13 is provided above the classification rotor 2a, from which raw material powder is supplied to the classification chamber 15. The coarse powder outlet 22 is provided below the classification rotor 2b. The gas is introduced from the gas inlets 20a and 20b opened to both tangential directions on the circumference of the classification rotors 2a and 2b.

A flow space is formed between the upper disks 6a and 6b by the generation of flowing air accompanying the rotation of the upper disks 6a and 6b. In this flow space, the powder is dispersed. Thus, powder agglomeration can be prevented by the dispersing action of the powder in the flow space, the fine powder yield can be increased, and the fine powder can be prevented from being mixed into the coarse powder, thereby improving the classification accuracy.

The toner was classified using a tandem classifier (200TTSP, manufactured by Hosokawa Micron Corporation) in which the classification rotor 2 shown in FIG. The classification rotor 2 was operated at an upper and lower rotational speed of 5000 rpm. A color toner having an average particle size of 5.1 μm (weight basis) and a fine powder content of 4 μm or less of 65.2% (number basis) was used as the raw material toner. In addition, coarse powder becomes a product also in the following Examples 1 and 2 and Comparative Example 1.

Example 1
Four deflection plates 28 are attached to the upper and lower guide vane rings 5 at an angle of about 20 degrees with respect to the center O of the classification rotors 2a and 2b, respectively, in the rotational direction of the classification rotors 2a and 2b. The clearance between the tip of the deflection plate 28 and the classifying rotors 2a and 2b was about 3.5 mm. Here, the distance between the outer peripheral surface of the classifying rotor 2 and the inner peripheral surface of the guide blade ring 5 is about 18 mm, and the length of the deflecting plate 28 is set to about 14 mm. The feed rate of the raw material was 70 kg / h. As a result, the coarse powder yield was 69.3%, the average particle size was 5.6 μm (weight basis), and the content of fine powder of 4 μm or less contained in the coarse powder was 12.1% (number basis).

(Example 2)
Eight deflection plates 28 were attached to the upper and lower guide blade rings 5 respectively. Otherwise, the operation was performed under the same conditions as in Example 1. As a result, the coarse powder yield was 57.2%, the average particle size was 5.7 μm (weight basis), and the content of fine powder of 4 μm or less contained in the coarse powder was 4.8% (number basis).

(Comparative Example 1)
Using the same guide vane ring 5 as in Example 1 and without the deflection plate 28 attached, the toner powder was classified. The operation was performed under the same conditions as in Example 1 except that the feed rate of the raw material was 48 kg / h. As a result, the coarse powder yield was 56.1%, the average particle size was 6.0 μm (weight basis), and the content of fine powder of 4 μm or less contained in the coarse powder was 27.3% (number basis). Although the feed rate of the raw material is lower than those in Examples 1 and 2, there is much mixing of the fine powder into the coarse powder, the dispersion is insufficient, and a good classification result is not obtained.

Thus, by attaching the deflection plate 28 to the guide blade ring 5, the content of fine powder of 4 μm or less contained in the coarse powder could be significantly reduced. In particular, in Example 1, although the raw material supply rate was increased as compared with Comparative Example 1, the coarse powder yield was high and the content of fine powder of 4 μm or less was low. Also in Example 2, the content of fine powder of 4 μm or less contained in the coarse powder was lower and the yield of coarse powder was higher than in Comparative Example 1, but the coarse powder yield was higher than in Example 1. The rate has dropped. This is because, as a result of increasing the number of deflecting plates 28, more toner powder stays in the vicinity of the classification rotor 2, so that coarse powder that should not flow into the classification rotor 2 originally becomes the classification rotor 2. It is thought that it has flowed out to the fine powder side. Therefore, in this case, it is considered that the gap between the deflection plate 28 and the outer peripheral surface of the classification rotor 2 needs to be wider. Therefore, regarding the number and size of the deflecting plates 28, in addition to the size of the classification rotor 2 and the guide blade ring 5 and the interval between them, the rotation speed of the classification rotor 2, the supply speed of the raw material, and the amount of gas introduced It is adjusted together with the operating conditions.

As described above, as a result of comparing Examples 1 and 2 with Comparative Example 1, the present invention can effectively remove fine powder and sufficiently ensure the yield of coarse powder as a product.

The classifier of the present invention removes fine powder from the powder after removing coarse particles, and classifies various powder materials in addition to toners, powder coatings, minerals, foods and feeds that use the coarse powder as a product. It can be done efficiently.

DESCRIPTION OF SYMBOLS 1 Casing 2 Classification rotor 3 Drive shaft 4 Discharge rotor 5 Guide blade ring 5a Guide blade 6 Upper disk 7 Lower disk 8 Classification blade 9 Dispersion blade 10 Top plate 11 Bottom plate 12 Blade 13 Raw material supply port 14 Opening 15 Classification chamber 16 Spiral Shaped member 17 Gas inlet chamber 18 Fine powder reservoir 19 Coarse powder reservoir 20 Gas inlet 20a Gas inlet 20b Gas inlet 21 Fine powder outlet 21a Fine powder outlet 21b Fine powder outlet 22 Coarse powder outlet 23 Seal member 24 Annular disk (Centifugal ring)
25 discharge vane 26 passage 27 air chamber 28 deflecting plate 29 strip member 30 hinge 31a drive motor 31b drive motor

Claims (5)

In a casing having a raw material supply port in the upper part and a coarse powder discharge port in the lower part, a classification rotor having a plurality of classification blades rotating around the rotation axis, and a gas introduction port with a predetermined interval on the outer peripheral surface of the classification rotor Coarse powder storage provided with a guide vane ring composed of a plurality of communicating guide vanes, allowing fine powder to flow into the classification rotor together with the gas supplied through the guide vane ring, and providing coarse powder below the guide vane ring In the classifier configured to flow into and out of the chamber, a deflector plate is provided on the inner peripheral surface of the guide vane ring, and the tip of the deflector plate is attached closer to the classifying rotor than the tip of the guide vane A classifier characterized by that.   The classifier according to claim 1, wherein the deflection plate is attached to a tip end portion of the guide blade on the rotational direction side of the classification rotor with respect to the guide blade ring.   3. The classifier according to claim 1, wherein the deflecting plate is attached to a spiral member provided in an annular space between an inner peripheral surface of the guide blade ring and an outer peripheral surface of the classifying rotor.   The deflecting plate is inclined 20 degrees to 70 degrees toward the rotation direction of the classifying rotor with respect to the center of the classifying rotor, and the clearance between the tip of the deflecting plate and the outer peripheral surface of the classifying rotor is 3 mm to 12 mm. The classifier according to claim 1, wherein the classifier is characterized by the following. The classifier according to any one of claims 1 to 4, wherein a plurality of the classifying rotors are coaxially connected to each other.