JP4147489B2 - Cylindrical screen classifier - Google Patents

Description

  This invention relates to inorganic materials such as gold and silver powder, nickel powder, calcium carbonate, alumina, silica, and other inorganic chemicals, organic compounds such as thermoplastic resins and thermosetting resins, cosmetics such as pharmaceuticals, foods, and foundations, and electrostatic images. The present invention relates to a cylindrical screen classifier for sieving powdery raw materials such as toner for phenomenon and powder paint.

This kind of cylindrical screen classifier is based on a plate-like rotor blade that is slightly fixed with a twist angle on a rotating shaft that rotates at high speed via a support disk, Is dispersed and swirled along the inner surface of the cylindrical screen, and a centrifugal force several tens of times the gravity is applied to the powdery raw material. The product that is coarser than the mesh of the cylindrical screen remaining on the inner surface of the cylindrical screen is discharged from the other end of the cylindrical screen to be the product on the net.
Since the cylindrical screen is a synthetic fiber woven net stretched in the direction of the center line, high-frequency fine vibration with a small support width is generated in each part, and the mesh of the cylindrical screen is not clogged.
Thus, such a cylindrical screen classifier exhibits a large sieving ability per unit area in a fine classification of several mm or less.

  However, fine powders of 0.2 mm or less generally have strong adhesion and aggregation properties. Therefore, in order to efficiently classify these raw materials, in order to improve the dispersion of the raw materials and / or to reduce the layer thickness, a flexible powder is required. A rotating blade of an elastic body having a suitable material and shape, or a shielding disk of the input material at right angles to the rotating shaft on the inlet side and / or outlet side of the rotating shaft in the cylindrical screen that rotates around this center (Especially when the cylindrical screen is a short cylinder) (see, for example, Patent Document 1 and Patent Document 4).

  In addition, in order to efficiently classify raw materials (for example, fine powders such as electrostatic image phenomenon toners and powder paints) that have strong adhesion and cohesion properties and are strongly charged with static electricity, several to dozens are provided inside the cylindrical screen. It is effective to insert individual elastic balls (see, for example, Patent Document 2 and Patent Document 3).

Japanese Patent No. 1714232 Japanese Patent No. 1789918 Japanese Patent No. 3513325 Japanese Patent No. 1497227

However, it has been found that the conventional examples so far have the following problems.
That is, a vortex group having a size corresponding to the width of the flat blade is generated on the back side of the flat blade rotating at high speed (high speed) in a direction that prevents the rotation of the rotary blade. The fine powder that should pass through the mesh is discharged into the vortex group before passing through the mesh, so that the classification efficiency of the cylindrical screen is deteriorated and the processing capacity is lowered.
This tendency becomes more prominent as the width of the rotor blade is wider, the rotation speed is higher (speed is higher), and the mesh of the cylindrical screen is finer (150 microns or less, especially 100 microns or less). .

  In view of the above circumstances, an object of the present invention is to improve the classification efficiency even if the screen of the cylindrical screen is fine or the cylindrical screen is a short cylinder. Another objective is to increase processing power.

The present invention provides a space between a cylindrical screen of a synthetic fiber woven mesh, one end of which is fixed to the inlet side mounting frame and the other end is fixed to the outlet side mounting frame, and a rotating shaft that rotates on the center line of the cylindrical screen. A support disk perpendicular to the rotation axis and centered on this center line , and radially attached to the outer periphery of the support disk at equal intervals , and inclined with respect to the center line of the cylindrical screen And a rotary screen provided with a small gap between the outer edge of the rotary blade and the inner surface of the cylindrical screen. It is a triangle, and is characterized in that there is one plane portion of the triangular cross-sectional shape on the upstream side in the rotational direction and one of the ridge line portions of the triangular cross-sectional shape on the downstream side in the rotational direction.

The ratio (B / L) of the width (B) of the rotary blade of the present invention to the diameter (L) of the cylindrical screen is 0.02 to 0.10 .

The tip on the outlet side of the rotor blade of the present invention is bent in the direction of 10 ° to 30 ° rotation .

The cylindrical screen of the present invention is a short cylinder and is in the cylindrical screen,
This embodiment is characterized in that a shielding disc of the input raw material is provided at a right angle to the rotating shaft on the inlet side and / or outlet side of the rotating shaft rotating at the center.

  The mesh opening of the cylindrical screen of the present invention is characterized by being 150 microns or less.

  The material and shape of the rotor blade according to the present invention is an elastic body having flexibility.

  The present invention is characterized in that an elastic ball for preventing clogging of mesh is placed inside the cylindrical screen of the present invention, and an elastic ball jump-out preventing plate is provided on the outlet side of the cylindrical screen. The drawings relating to the present invention include “FIG. 1” in Patent Document 4 (Patent No. 1497227), but in general, “cylindrical screen of reference numeral 9” in each figure in the section “Brief Description of Drawings”. Since the axial length of “is shortened, the illustration is omitted.

Start the cylindrical screen classifier rotates the rotating blades inside the cylindrical screen, when introduced in feeder screw such from the supply section the powdery raw material into the cylindrical screen, as shown in FIG. 4-a (reference drawing) Furthermore, a vortex group 21 having a size corresponding to the width B of the flat blade and the number of rotations is generated on the back surface side of the flat blade 13 in the traveling direction so as to prevent the rotation of the rotary blade. It was discovered that fine powder that should pass through the 9 mesh is caught in the vortex group 21 and discharged to the coarse powder side without passing through the mesh, resulting in poor classification efficiency of the cylindrical screen and reduced processing capacity.
This tendency becomes more prominent as the width of the rotor blade is wider, the rotation speed is higher (speed is higher), and the mesh of the cylindrical screen is finer (150 microns or less, especially 100 microns or less). I also understood that.

In order to reduce the number of vortex groups generated on the back side in the traveling direction of the flat-plate-shaped rotor blade as much as possible, increase the classification efficiency, and simultaneously increase the processing capacity, the following best method was actually found.
That is, a synthetic fiber woven mesh cylindrical screen having one end fixed to the inlet-side mounting frame and the other end fixed to the outlet-side mounting frame, and a rotating shaft that rotates on the center line of the cylindrical screen are spaced apart from each other. A support disk having a center perpendicular to the rotation axis and centered on the center line, and a rotor blade radially attached to the outer periphery of the support disk at equal intervals, the outer edge of the rotor blade and the cylindrical screen in the cylindrical screen classifier having a rotating blade provided so that there is a small gap between the inner surface, the cross-sectional shape of the rotor blade is a triangle, of the triangular cross-section on the upstream side in the rotational direction There is one plane portion and one ridge line portion of the triangular cross-section on the downstream side in the rotational direction , and furthermore, the ratio of the width (B) of the rotary blade to the diameter (L) of the cylindrical screen (B / L) is 0.02 to 0.10. To solve the above problems was pending until now I was able.

Also, the material and shape are flexible and / or elastic, and an elastic ball for preventing clogging of the mesh is put inside the cylindrical screen, and the elastic ball is prevented from jumping to the outlet side of the cylindrical screen. Needless to say, the present invention can be applied progressively to the provision of a plate, the bending of the tip of the rotor blade on the outlet side to the direction of rotation of 10 ° to 30 °, and the like.

An embodiment of the present invention will be described with reference to FIGS. 5 to 8 are reference views that are the same as those of the embodiment of the present invention except for the rotor blade portion.
The cylindrical screen classifier used was a TS125 × 200 type turbo screener (diameter and length of the cylindrical screen 9: φ125 × 200 L) manufactured by Turbo Industry Co., Ltd., and the cylindrical screen was a polyester net, The mesh opening was 42 microns, and the rotational speed 9a of the rotor shaft 8 was 1200 r / min.
A net product case 2 is provided on one end face of the casing 1, and a raw material supply case 3 is provided on the other end face. The lower part of the casing 1 is a fine powder outlet chute 7.
Inside the cylindrical screen 9, there are a plurality of rotary blades 13 [polyacetal flat plate, the width of which is 11 mm (B / L = 0) in which the outlet end 13a is bent β = 20 ° in the direction of rotation 9a. 0.088) and the comparative example was 22 mm (B / L = 0.176). The elastic ball (polyurethane ball) is prevented from jumping out by a shielding disc 31 on the exit end side of the cylindrical screen, and seven elastic balls 30 for preventing clogging of meshes are placed.
In the figure, 4 is a raw material feeder (screw feeder in this figure), 5 is a bearing case, 6 is a rotation main shaft, 9a is a rotation direction, 10 is an entrance side screen mounting frame, and 10c is a screen mounting band ( Inlet side), 11 is an outlet side screen mounting frame, 11c is a screen mounting band (exit side), 12 is a screen tension rod, 14 is a rotating blade support disk or rotating support frame, 15 is a baffle plate, 16 is Bearing device (bearing, etc.), 17 is a shaft seal device (oil seal, etc.), 20 is a raw material charging direction, 20a is a fine powder (under sieve product) discharging direction, 20b is a sieving product discharging direction, and α is an inclination angle of the rotor blade. , Respectively.

  The raw material was a one-component toner, and the median diameter (d50) was 8 microns.

In the example, the processing capacity was 59 kg / hr, and the classification efficiency (yield under sieve) was 98.5%. On the other hand, in the comparative example, the processing capacity was 49 kg / hr, and the classification efficiency (yield under sieve) was 94.5%.
In both the examples and the comparative examples, no clogging was observed in the woven mesh of the cylindrical screen. From this, it is clear that the present invention in which the width of the rotary blades (flat plate blades) of the cylindrical screen classifier is narrower is superior both in terms of processing capacity and classification efficiency (under-sieving yield).

There is no need to specify anything as long as the rotor blades are flexible or have an elastic body, but they have good wear resistance and chemical resistance. Polyacetal / ultra high molecular weight polyethylene -Resins such as MC nylon and Teflon (registered trademark) , metals such as stainless steel, aluminum, and special alloy steel, glass fiber, plywood, etc. There are painted ones.
Also, as the screen material for the cylindrical screen, various resins such as polyethylene, polyester, and nylon are mainly used, but stainless steel or the like is used depending on the type of raw material and the mesh screen opening of the cylindrical screen. It is possible that
Examples of the material of the elastic ball for preventing clogging of the mesh include various synthetic rubbers, NBR, polyurethane rubber, silicon rubber, and the like.

  Compared with the conventional comparative example, the embodiment of the present invention only reduces the width of the rotor blade (22 mm → 11 mm), and suppresses the generation of vortex groups that obstruct sieving and classification. Both capacity and classification efficiency (yield under sieve) could be increased.

It is a left view which shows the Example of this invention. It is a front view which shows the Example of this invention. FIG. 3 is a central longitudinal sectional view of FIG. 2. FIG. 4 is a reference view, and is a reference cross-sectional view corresponding to the cross-sectional view taken along the line XX of FIG. 3. It is the XX sectional view taken on the line of FIG. It is a reference vertical cross-sectional view. A dotted line in the vicinity of the center line in the figure schematically shows a state in which the rotating blade in operation is bent. It is II sectional drawing of FIG. It is a reference longitudinal cross-sectional view. It is II-II sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Sieve product case 3 Raw material supply part 4 Raw material supply machine (In this figure, all are screw feeders.)
5 Bearing case 6 Rotating spindle 7 Fine powder (under sieve product) outlet chute 8 Rotor shaft 9 Cylindrical screen 9a Rotating direction 10 Inlet side screen mounting frame 10c Screen mounting band (inlet side)
11 Exit side screen mounting frame 11c Screen mounting band (exit side)
12 Screen tension rod 13 Rotor blade 13a Bent portion of rotor blade outlet end 14 Rotor blade support disk or rotor blade support frame 15 Baffle plate 16 Bearing device (bearing, etc.)
17 Shaft seal device (oil seal, etc.)
20 Raw material loading direction 20a Fine powder (under-sieving product) discharging direction 20b Over-sieving product discharging direction 21 Vortex group 30 Elastic ball 31 Shielding disc (elastic ball pop-out prevention plate)
α Inclination angle of rotor blade β Bending angle of rotor blade outlet

Claims (7)

Synthetic fiber woven mesh cylindrical screen, one end of which is fixed to the inlet side mounting frame and the other end is fixed to the outlet side mounting frame, and a rotating shaft that rotates on the center line of the cylindrical screen. A support disk perpendicular to the axis and centered on this center line , and a rotor blade attached radially to the outer periphery of the support disk at equal intervals and inclined with respect to the center line of the cylindrical screen And a rotary blade provided with a small gap between the outer edge of the rotary blade and the inner surface of the cylindrical screen,
The rotary blade has a triangular cross-sectional shape, and has one plane portion of the triangular cross-sectional shape on the upstream side in the rotational direction and one ridge line portion of the triangular cross-sectional shape on the downstream side in the rotational direction. Cylindrical screen classifier.   The cylindrical screen classifier according to claim 1, wherein the ratio (B / L) of the width (B) of the rotary blade and the diameter (L) of the cylindrical screen is 0.02 to 0.10. .   The cylindrical screen classifier according to claim 1 or 2, wherein a tip on the outlet side of the rotor blade is bent in the direction of rotation of 10 ° to 30 °.   The cylindrical screen is a short cylinder, and a shielding disk of the input material is provided at right angles to the rotating shaft on the inlet side and / or outlet side of the rotating shaft that rotates in the center of the cylindrical screen. The cylindrical screen type classifier according to claim 1, 2, or 3.   The cylindrical screen classifier according to claim 1, 2, 3, or 4, wherein the mesh opening of the cylindrical screen is 150 microns or less.   6. The cylindrical screen classifier according to claim 1, 2, 3, 4, or 5, wherein the rotor blade is made of an elastic body having a flexible material and shape. An elastic ball for preventing clogging of mesh is placed inside the cylindrical screen, and a jump-out preventing plate for the elastic ball is provided on the outlet side of the cylindrical screen. Or the cylindrical screen type classifier of 6.

Images