JP3361823B2 - Cyclone type dry classifier - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cyclone type dry classification apparatus characterized in that the classification point of powder can be changed. BACKGROUND OF THE INVENTION The necessity of classifying powders has recently been gradually increased with the development of the ceramics industry and the like, the advancement of technology, and the advancement of technology. There is a growing demand for improvements, treatment of large amounts of powder, reduction of classification costs, reduction of equipment costs by simplifying the structure of the classification device, easier maintenance and inspection, prevention of contamination during classification, and improvement of the performance of the device. Is coming. As a device for classifying powder in a dry manner, a device of a forced vortex type using a centrifugal force by rotating a rotor is conventionally known. This has the feature of being excellent in classification performance, but has a mechanically operating part that rotates the rotor as described above,
There is a problem that the structure is complicated, the device is likely to be expensive, and the burden of maintenance and inspection is not small. As a dry classifier, a cyclone classifier for classifying powders of several microns to submicron may be used in addition to the forced vortex type apparatus as described above. This cyclone type classification device has an opening for blowing an air flow containing dispersed powder in a dry state in a horizontal direction along an inner wall surface above a generally upright cylindrical cyclone tower main body. A powder blowing pipe extending from the opening in a tangential direction of the cyclone tower main body, and a supply air flow is blown from the powder blowing pipe to form a vortex in the cyclone tower main body, which is included in the vortex Coarse powder having a large bulk specific gravity among the powders gradually settles down on the vortex, and is collected by a coarse powder collection means comprising a casing or a tube provided at a lower portion of the tower main body. Fine powder with low specific gravity
Ru der those made from the cyclone tower configured to weak inhales by applying suction recovery from above the center of the vortex of the column body. FIG. 5 shows an outline of the structure of a conventional cyclone classifier. In FIG. 5, reference numeral 1 denotes a powder feeder, which stores powder to be classified and is continuously fed by a feeder screw 1a. This powder is supplied to the lower powder dispersing machine 2. The powder dispersing machine 2 is for dispersing the powder in the agglomerated state into the state of primary particles, and a known one can be used as appropriate. The powder that has passed through the powder disperser 2 is blown into the powder introduction section 6 of the cyclone tower 5 together with air from the air intake through the powder transport pipe 3. The cyclone tower main body has an upright cylindrical shape, and is composed of an upper straight cylindrical portion 5a and a lower funnel-shaped tapered portion 5b, and the lower end is open to the coarse powder storage tank 8. From the ceiling of the cyclone tower 5, a primary air take-out cylinder 7 for taking out fine powder is hung down to a position at a constant height inside the tower main body,
A negative pressure from the blower 10 is applied. Reference numeral 7b denotes a filter provided in the fine powder transport pipe 7a for collecting fine powder. [0008] According to the cyclo-tube type classification device having such a structure, the coarse particles settle on the vortex, and the fine particles are extracted from the upper part by the weak negative pressure from the primary air extraction cylinder 7. Therefore, there is an advantage that there is no moving part such as a rotary rotor and the like, and the burden of maintenance and inspection is small. The above-mentioned cyclone type dry classifier is generally capable of classifying fine powder (usually about 1 μm) in a simple and inexpensive manner. The classifier can vary the classification point by varying the rotation speed of the rotating rotor, whereas the cyclone classifier has a fixed classification point determined by the structure of the cyclone tower, etc. Since it is difficult to classify powders with different classification points using one device, there is a problem that it is not suitable for application to equipment that needs to change the classification point according to changes in manufacturing conditions and quality. is there. The present invention has been made in view of the above-mentioned situation, and has as its object to provide a cyclone type classification device capable of changing a classification point. Another object of the present invention is to realize a configuration for changing a classification point in a cyclone type classification device by a relatively simple structure, and to have a simple structure and a small burden of maintenance and inspection. It is an object of the present invention to provide a classifier capable of fully utilizing the features of the classifier. [0012] To achieve the above object, the present inventors provide a cyclone type classification apparatus having no mechanically operating part, and a classifier which is industrially sufficiently useful. The cyclone type dry classifier of the present invention was completed with a classifier capable of ensuring the characteristics. That is, the feature of the cyclone-type dry classification device according to the present invention is that an upright cylindrical cyclone tower main body and an air flow containing powder subjected to dispersion treatment are applied along the inner wall surface of the cyclone tower main body. for blowing the circumferential direction, and the powder introduction guide section the radius of the tower top to the top of the cyclone tower body is extended in the circumferential direction so as to gradually increasing tangential cyclone tower body outward from the powder introduction guide portion And a powder blowing pipe extending in the direction, and dispersing the powder from the powder blowing pipe.
An air stream containing the treated powder is blown to form a vortex in the cyclone tower main body, and coarse powder having a large bulk specific gravity settling on the vortex is collected at a lower portion of the tower main body, while the small bulk specific gravity is small. In the cyclone-type dry classifier configured to collect weak air by applying weak suction from above to the center of the vortex in the tower body, the fine powder is connected from the powder blowing pipe to the powder introduction guide. From the position of the part
One end of the cyclone is connected to the
The cyclone is located at the radial inner edge located just above the inner wall of the tower body.
Arc with a gradual change in curvature against the inner wall of the tower body
And the other end side is the circumferential inner wall of the powder introduction guide.
1/4 of at least cyclone tower body Migihitsuji suited to the surface
An arc-shaped orbit whose radius of curvature gradually increases over the circumference
Set and advance along this trajectory to
The advance retractable sliding wall of the air flow with de section wall can be reduced blown tip aperture cross-section is provided, there is to forming a structure that further provided to advance retraction means of the slide wall. In the above structure, the powder introduction guide portion for introducing the powder into the cyclone tower has an inner peripheral wall surface for powder guide (hereinafter, referred to as a guide wall surface) whose diameter gradually increases along the circumferential direction. The circumferential spiral structure type having the above is preferable. The classification performance of the coarse and fine powders in the cyclone tower main body is also affected by the state of gas transport after the classification. For this reason, for example, since coarse powder is smoothly dropped and discharged from the lower part of the cyclone tower main body, since it has a favorable effect on the improvement of the classification performance, for example, in a coarse powder storage tank provided to face the lower end of the tower main body, It is also preferable to connect a secondary air outlet cylinder. Thereby, the state where the coarse powder falls from the coarse powder storage tank becomes smooth, and the classification performance with the fine powder taken out from the upper part of the cyclone tower main body by the negative pressure is improved. [0016] In the present invention, the sliding wall is assumed that an arc shape provided to be advanced retracted generally circumferential direction towards the inner wall of the powder introduction guide section from the position immediately above the inner wall surface of the cyclone tower body You. Such a slide wall is formed in such a manner that a metal or plastic plate is formed in an arc shape in advance and this is made to enter and exit the tower from the outside of the tower main body, or provided so as to protrude radially outward from the tower main body. A guide groove is provided at the bottom and the ceiling of the powder introduction guide, and the plate can be easily formed by sliding the bendable plate. According to the structure of the present invention, by reducing the cross-sectional area of the air flow blowing tip by the advance of the arc-shaped slide wall, the flow velocity of the blown air flow is increased, and the classification point is shifted to the minute diameter side. Transition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. The present embodiment is characterized in that a slide wall is provided in the powder introduction section of the cyclone tower, and the other configuration is that the classification device is configured in the same configuration as that described with reference to FIG. Can be. Therefore, in the present embodiment described with reference to FIGS. 1 to 3, only the powder introduction part of the cyclone tower is shown, and other parts are not shown. In FIGS. 1 to 3, reference numeral 31 denotes an upright cylindrical cyclone tower (only the upper part is shown), and the upper part of the cyclone tower projects radially outward from the wall surface of a tower body 32 having a cylindrical shape. A spiral guide wall 33 whose radius gradually increases in an arc over substantially one round is provided, and a powder introduction portion 34 is provided.
Is formed. 35 is a bottom surface of the powder introduction part 34, 3
Reference numeral 6 denotes a ceiling surface of the powder introduction unit 34. Reference numeral 37 denotes a rectangular tube-shaped air flow blowing pipe connected to the end maximum diameter portion of the powder introduction section 34. Reference numeral 38 denotes a primary air take-out cylinder 7 for taking out fine powder. In addition to the above configuration, in the present embodiment, at the connection portion of the air flow blowing pipe 37 to the end of the powder introduction portion 34, the inside of the powder introduction portion from the radial inner edge portion is connected. And a highly rigid arc-shaped slide wall 40 formed in advance with the curvature so as to be able to advance to the right side, and is advanced and retracted to an appropriate position by driving means such as a motor (not shown). It has become so. The dashed line in FIG. 1 shows a state in which the slide wall 40 has entered the powder introduction section to the maximum. The following test was conducted to confirm the classification performance of the cyclone type classification device having the slide wall having the above-described configuration. Structure of the cyclone tower Diameter of the (upper) straight cylindrical part of the tower body: 72 mm Diameter of the lower end of the tapered part of the tower body: 40 mm Height of the tower body:・ ・ ・ 350mm Width of maximum diameter part of powder introduction part ・ ・ ・ ・ ・ ・ 17mm Vertical dimension of powder introduction part ・ ・ ・ 40mm含粉body blowing velocity (air flow blowing pipe) of an air flow 20.0 m / s blown powder · · · JIS standard powder (Kanto _{loam: D p = 1.8μm, ρ p} = 3g / cc) powder blow In the cyclone tower having a configuration of 100 g / h or more, the leading end position of the slide wall 40 is set in six stages of A to F in FIG. In each case, the gap between the leading end of the slide wall 40 and the guide wall 33 and the space passing through this gap The flow rate of the airflow was measured and the results are shown in Table 1 below. The classification efficiency of coarse powder and fine powder was measured and the results are shown in FIG. [Table 1] As can be seen from the test results, it is clear that the classification point of the same powder can be changed by advancing the slide wall. As described above, according to the present invention, the classification point can be changed in the cyclone type classification apparatus, and the problem of the cyclone type classification apparatus which can only perform classification at the fixed classification point conventionally. This has the effect of improving the point and increasing its usefulness. Further, according to the present invention, since the structure for changing the classification point in the cyclone type classification device can be realized by a simple structure in which the slide wall advances and retreats, the cyclone has a simple structure and a small burden of maintenance and inspection. There is also an effect that the features of the type classification device can be fully utilized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional plan view showing an outline of a configuration of a powder introduction section of a cyclone type dry classification device according to one embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the same. FIG. 3 is a view showing an advanced position of a slide wall according to the embodiment. FIG. 4 is a diagram showing a result of measuring classification efficiency. FIG. 5 is a diagram showing an outline of the overall configuration of a cyclone-type tubular classifier to which the present invention is applied. [Description of Signs] 1: powder feeder, 2 powder disperser: 3: powder transport tube, 5: cyclone tower, 6: powder introduction unit, 7: primary air extraction cylinder, 8: coarse powder storage tank , 10: blower, 31: cyclone tower, 32: straight tube portion, 33: guide wall, 34: powder introduction portion, 35: bottom surface, 36: ceiling surface, 37: air blowing tube, 38: primary air extraction tube, 40 : Sliding wall.

   ────────────────────────────────────────────────── ─── Continuation of front page    (73) Patent holder 591112603               Hideto Yoshida               1-4-1 Kagamiyama, Higashihiroshima City, Hiroshima Prefecture (72) Inventor Koichi Iitani               2-7 Tanaka Sekidacho, Sakyo-ku, Kyoto (72) Inventor Hideto Yoshida               1-4-1 Kagamiyama, Higashihiroshima City, Hiroshima Prefecture (72) Inventor Hideo Moriyama               2-12-3 Nishikata, Bunkyo-ku, Tokyo (72) Inventor Yukiyoshi Ueda               3-6-18 Hachiman, Kawashima-cho, Hiki-gun, Saitama Prefecture (72) Inventor Tadashi Fuyuki               2-23-16 Midorigaoka, Oimachi, Iruma-gun, Saitama                (56) References JP-A-64-75054 (JP, A)                 Shokai Sho 57-55553 (JP, U)                 Jiko 29-16797 (JP, Y1)

Claims (1)

(57) [Claims 1] An upright cylindrical cyclone tower main body and an air flow containing dispersed powder are blown circumferentially along the inner wall surface of the cyclone tower main body. A powder introduction guide portion extending along the circumferential direction at the upper portion of the cyclone tower main body so that the radius of the tower gradually increases, and a tangential direction extending from the powder introduction guide portion to the outside of the cyclone tower main body. And a blown air stream containing the dispersed powder is blown from the blown pipe to form a vortex in the cyclone tower main body, and a bulk specific gravity settled by the vortex flow is provided. Cyclone-type dry type, which is configured to collect large coarse powder at the bottom of the tower body, while collecting fine powder having a small bulk specific gravity by applying weak suction from above to the center of the vortex in the tower body from above. In the classification device, the powder blowing pipe The connection to the powder introduction guide section, rhinoceros
From the position directly above the inner wall surface of the Klong tower body, the powder introduction guide section
Slide wall that forms an arc in the circumferential direction toward the inner wall of the
In addition to providing
A cyclone-type dry classification device, wherein the slide wall is advanced from the radially inner edge of the connection portion into the powder introduction guide portion so as to vary the cross-sectional area of the airflow blowing tip.