WO2010071253A1

WO2010071253A1 - Stirred ball mill

Info

Publication number: WO2010071253A1
Application number: PCT/KR2008/007865
Authority: WO
Inventors: Hyun Ho Chun; Young Hyun Nam; Tae Youn Kim
Original assignee: Je Powder Co., Ltd.
Priority date: 2008-12-19
Filing date: 2008-12-31
Publication date: 2010-06-24
Also published as: KR100928076B1

Abstract

Provided is a stirred ball mill. The stirred ball mill includes: an internal tube which has a cylindrical shape and in which a screen through which a raw material having a size less than a predetermined size is passed is disposed on an outer circumferential surface of the internal tube; a plurality of first pins coupled to an outer circumferential surface of the internal tube; a cylindrical centrifugal separator comprising a coupling groove formed in a middle of a top surface of the centrifugal separator and a plurality of bead discharge holes formed in edges of the top surface of the centrifugal separator, a bottom surface of the centrifugal separator being opened so that the internal tube is inserted in the centrifugal separator; a plurality of second pins coupled to an outer circumferential surface of the centrifugal separator; a cylindrical casing comprising an insertion hole formed in a middle of a top surface of the casing and a material inlet arranged at one end of the casing, the internal tube and the centrifugal separator being inserted in an opened lower portion of the casing; a bottom plate coupled to the opened lower portion of the casing so as to close an inside of the casing and comprising a material outlet arranged in a middle of the bottom plate, a bottom end of the internal tube being fixed on a top surface of the bottom plate; a plurality of beads disposed to move in a space formed between the internal tube, the centrifugal separator, and the casing; a shaft inserted in the insertion hole and coupled to the coupling groove; and a sealing member sealing a space between the insertion hole and the shaft. Since the beads can be forcibly discharged and circulated through the bead discharge holes formed in the separate centrifugal separator, the screen is not clogged, and circulation is smoothly performed so that a strong milling force can be transferred to the raw material.

Description

Description STIRRED BALL MILL

Technical Field

[1] The present invention relates to a stirred ball mill, and more particularly, to a stirred ball mill that is used for stirring and milling of a material by using beads. Background Art

[2] In recent times, technical fields in which nano powder exceeding micropowder is used are increasing. For example, the technical fields in which nano powder is used, such as nanorization of dyes, pigments or paints for realizing various colors, production of high-priced ceramic materials, nano dispersion of metals for development of a new composite material, development of cosmetics that are appropriate to advanced countries regulation, and production and application of a prototype product manufactured by a medicine company, are continuously increasing.

[3] In order to form nano powder, in particular, when metal power is formed, wet milling other than conventional dry milling that is at risk of explosion is appropriate. Nano grinding machine is manufactured to form ultra fine powder in a wet manner and is called a stirred ball mill.

[4] A milling method by using a conventional stirred ball mill is as below.

[5] FIG. 1 is a cross-sectional view of a conventional stirred ball mill. Referring to FIG.

1, first, a slurry which is a liquid phase material is sucked into a cylindrical external casing 10 through an inlet 11 arranged below the external casing 10. When a drive shaft 30 is rotated by an additional drive member, a cylindrical rotator 20 connected to the drive shaft 30 also rotates. A plurality of pins 21 are arranged on an outer circumferential surface of the rotator 20, and a plurality of balls 40 are arranged in a space between the external casing 10 and the rotator 20. When the pins 21 are rotated by rotation of the rotator 20, the liquid phase slurry is rotated and collides with the balls 40, and then the slurry is milled. Gaps formed in a screen 50 disposed above the rotator 20 are fine so that the milled material slurry can be filtered through the screen 50. Thus, the balls 40 cannot deviate from the space between the external casing 10 and the rotator 20. Thus, only the milled slurry is discharged from the external casing 10 through an outlet 12.

[6] However, when the fine balls 40 are used to form nano powder, the balls 40 are leaning to the screen 50, and the screen 50 is gradually clogged. When a material having comparatively large viscosity is to be processed by using the balls 40 having a general size, a part of the screen 50 is clogged, which results in a considerable increase in pressure of the stirred ball mill and hindrance in a milling process. In addition, when the fine balls 40 are used, the very fine screen 50 must be used. The screen 50 may be very easily damaged when the balls 40 collide with one another.

[7] Furthermore, there is a limitation in reducing the sizes of the gaps formed in the screen 50 due to a fabrication process. Thus, the balls 40 having a size of about 0.2 mm or less cannot be used. It is difficult to form nano-sized particles, and time required for forming uniform particles increases, and production is reduced. Disclosure of Invention Technical Problem

[8] The present invention provides a stirred ball mill in which efficient milling or dispersion can be performed without clogging of a screen due to balls. Technical Solution

[9] According to an aspect of the present invention, there is provided a stirred ball mill including: an internal tube which has a cylindrical shape and in which a screen through which a raw material having a size less than a predetermined size is passed is disposed on an outer circumferential surface of the internal tube; a plurality of first pins coupled to an outer circumferential surface of the internal tube; a cylindrical centrifugal separator comprising a coupling groove formed in a middle of a top surface of the centrifugal separator and a plurality of bead discharge holes formed in edges of the top surface of the centrifugal separator, a bottom surface of the centrifugal separator being opened so that the internal tube is inserted in the centrifugal separator; a plurality of second pins coupled to an outer circumferential surface of the centrifugal separator; a cylindrical casing comprising an insertion hole formed in a middle of a top surface of the casing and a material inlet arranged at one end of the casing, the internal tube and the centrifugal separator being inserted in an opened lower portion of the casing; a bottom plate coupled to the opened lower portion of the casing so as to close an inside of the casing and comprising a material outlet arranged in a middle of the bottom plate, a bottom end of the internal tube being fixed on a top surface of the bottom plate; a plurality of beads disposed to move in a space formed between the internal tube, the centrifugal separator, and the casing; a shaft inserted in the insertion hole and coupled to the coupling groove; and a sealing member sealing a space between the insertion hole and the shaft. Here, the centrifugal separator may include: a circular disc forming a body of the centrifugal separator; and a centrifugal separation discharge disc which is coupled to an upper portion of the circular disc and in which the coupling groove and the plurality of bead discharge holes are formed. Here, the centrifugal separator may be separated from the bottom plate.

[10] In addition, the first pins may be arranged so that a plurality of circular groups are formed on the outer circumferential surface of the internal tube along a horizontal line. Alternatively, the first pins may be arranged in a spiral form along a rotation direction of the centrifugal separator so as to give upward directivity to the beads. In addition, the second pins may be arranged in a spiral form along the rotation direction of the centrifugal separator so as to give downward directivity to the beads when the centrifugal separator is rotated. Furthermore, a plurality of second pins that are disposed in an upper position, of the second pins may be disposed in a spiral form along the rotation direction of the centrifugal separator so as to give downward directivity to the beads when the centrifugal separator is rotated, and a plurality of second pins that are disposed in a lower position, of the second pins may be disposed in a spiral form along a direction opposite to the rotation direction of the centrifugal separator so as to give upward directivity to the beads when the centrifugal separator is rotated. Furthermore, the stirred ball mill may further include a plurality of third pins coupled to an inner circumferential surface of the casing to cross the second pins so as to not collide with the second pins when the centrifugal separator is rotated.

[11] In addition, the sealing member may include a mechanical seal. Furthermore, the stirred ball mill may further include a cooling jacket arranged at an outside of the casing so as to cool the casing. Furthermore, the stirred ball mill may further include a driving member providing a driving force that is used to rotate the shaft.

Advantageous Effects

[12] According to the present invention, first, since the beads can be forcibly discharged and circulated through the bead discharge holes formed in the separate centrifugal separator, the screen is not clogged, and circulation is smoothly performed so that a strong milling force can be transferred to the raw material.

[13] Second, the beads and the raw material are easily separated from each other so that a milling or dispersion capability can be improved, productivity can be improved and a process time can be reduced.

[14] Third, due to the second pins disposed in upper and lower positions in an asymmetric spiral form, the beads collide with the middle of the space formed between the centrifugal separator and the casing.

[15] Fourth, the beads having a small size of about 0.05 mm can be used so that milling or dispersion of nano-sized particles having low viscosity can be performed.

Brief Description of the Drawings

[16] The above and other aspects of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[17] FIG. 1 is a cross-sectional view of a conventional stirred ball mill;

[18] FIGS. 2 and 3 are perspective views of an internal tube and a centrifugal separator according to an embodiment of the present invention;

[19] FIG. 4 is a cross-sectional view of a stirred ball mill according to an embodiment of the present invention;

[20] FIG. 5 is an exploded view of a side of the centrifugal separator illustrated in FIG. 2;

[21] FIG. 6 is a side view of the internal tube illustrated in FIG. 3; and

[22] FIG. 7 is a perspective view of a stirred ball mill according to an embodiment of the present invention. Best Mode for Carrying Out the Invention

[23] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. First, terms or words used in the present specification and the claims should not be construed as being limited to general or literal meaning, and the inventor should construe his/her own invention in meaning and concept that coincide with the technical spirit of the invention based on the principle for properly defining the concept of the terms so as to describe his/her own invention in the best manner.

[24] Thus, configurations shown in embodiments and the drawings of the present invention rather is an example of the most exemplary embodiment and does not represent all of the technical spirit of the invention. Thus, it will be understood that various equivalents and modifications that replace the configurations are possible when filing the present application.

[25] Hereinafter, a stirred ball mill M according to an embodiment of the present invention will be described.

[26] FIGS. 2 and 3 are perspective views of an internal tube and a centrifugal separator according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of a stirred ball mill according to an embodiment of the present invention. FIG. 5 is an exploded view of a side of the centrifugal separator illustrated in FIG. 2. FIG. 6 is a side view of the internal tube illustrated in FIG. 3. FIG. 7 is a perspective view of a stirred ball mill according to an embodiment of the present invention.

[27] Referring to FIGS. 2 through 7, the stirred ball mill includes an internal tube 100, a centrifugal separator 200, a casing 300, a plurality of beads 400, a shaft 500, and a sealing member 600.

[28] The internal tube 100 has a cylindrical shape, and a screen 120 through which a raw material R having a size less than a predetermined size is passed is disposed on an outer circumferential surface of the internal tube 100. A plurality of first pins 110 are coupled to the outer circumferential surface of the internal tube 100. The first pins 110 are disposed in a spiral form along a rotation direction of the centrifugal separator 200 so as to give upward directivity to the beads 400. The first pins 110 may be arranged so that circular groups can be formed on the outer circumferential surface of the internal tube 100 along a horizontal line.

[29] The centrifugal separator 200 also has a cylindrical shape, and a coupling groove 220 is formed in the middle of a top surface of the centrifugal separator 200, and a plurality of bead discharge holes 230 are formed in edges of the top surface of the centrifugal separator 200. A bottom surface of the centrifugal separator 200 is opened, and the internal tube 100 is inserted in the bottom surface of the centrifugal separator 200. A plurality of second pins 210 may be coupled to an outer circumferential surface of the centrifugal separator 200. The centrifugal separator 200 may be formed as one body. Alternatively, as illustrated in FIGS. 2 and 3, the centrifugal separator 200 may include a circular disc 200a and a centrifugal separation discharge disc 200b. The circular disc 200a forms a body of the centrifugal separator 200, and the centrifugal separation discharge disc 200b is coupled to an upper portion of the circular disc 200a, and the coupling groove 220 and the bead discharge holes 230 are formed in the centrifugal separation discharge disc 200b.

[30] When the centrifugal separator 200 is rotated, the second pins 210 are disposed in a spiral form along a rotation direction Dl of the centrifugal separator 200 so as to give downward directivity to the beads 400. Furthermore, referring to FIG. 5, a plurality of second pins 210a that are disposed in an upper position, of the second pins 210 are disposed in a spiral form along the rotation direction Dl of the centrifugal separator 200 so as to give downward directivity to the beads 400, and a plurality of second pins 210b that are disposed in a lower position, of the second pins 210 are disposed in a spiral form along a direction opposite to the rotation direction Dl of the centrifugal separator 200 so as to give upward directivity to the beads 400 when the centrifugal separator 200 is rotated.

[31] The casing 300 has a cylindrical shape, and an insertion hole 320 is formed in the middle of a top surface of the casing 300, and a material inlet 330 is arranged at one end of the casing 300. The internal tube 100 and the centrifugal separator 200 are inserted in an opened lower portion of the casing 300. A bottom plate 340 is coupled to the opened lower portion of the casing 300 so as to close an inside of the casing 300, and a bottom end of the internal tube 100 is fixed on a top surface of the bottom plate 340, and a material outlet 340a is arranged in the middle of the bottom plate 340. Here, the centrifugal separator 200 is separated from the bottom plate 340. A cooling jacket 350 is arranged at an outside of the casing 300 so as to cool the casing 300. Furthermore, a plurality of third pins 310 are coupled to an inner circumferential surface of the casing 300 to cross the second pins 210 so as to not collide with the second pins 210 described previously, when the centrifugal separator 200 is rotated.

[32] In addition, the beads 400 are disposed in the space formed between the internal tube 100, the centrifugal separator 200, and the casing 300 and move in the space.

[33] The shaft 500 is inserted in the insertion hole 320 and is coupled to the coupling groove 220 of the centrifugal separator 200, and a driving member 700 provides a driving force that is used to rotate the shaft 500. When a driving pulley 710 connected to the driving member 700 is rotated, a driven pulley 720 coupled to the shaft 500 by a V-belt 730 is rotated. The driven pulley 720 is connected to the shaft 500 so that relative rotation cannot be performed. A space between the insertion hole 320 and the shaft 500 is sealed by the sealing member 600. The sealing member 600 may be a mechanical seal that is generally used. In other words, a metal portion that rotates together with the rotation shaft 500 and a metal portion that is fixed on a gland are completely, closely adhered to each other, make a sliding motion and are maintained at an air-tight and liquid-tight state.

[34] Next, an operation of the stirred ball mill according to the current embodiment will be described.

[35] First, a material is supplied through the material inlet 330 arranged at one end of the casing 300, and the shaft 500 is rotated by the driving member 700. The raw material R is supplied in the form of liquid phase slurry. Then, the centrifugal separator 200 connected to the shaft 500 is rotated, and the second pins 210a that are disposed in an upper position A, of the second pins 210 are disposed in a spiral form along the rotation direction Dl of the centrifugal separator 200 when the centrifugal separator 200 is rotated, so as to give downward directivity to the beads 400, and the second pins 210b that are disposed in a lower position B, of the second pins 210 are disposed in a spiral form along a rotation direction D2 opposite to the rotation direction Dl of the centrifugal separator 200 when the centrifugal separator 200 is rotated, so as to give upward directivity to the beads 400 (see FIG. 5). In addition, the third pins 310 that are coupled to the inner circumferential surface of the casing 300 are disposed to cross the second pins 210 so as to not collide with the second pins 210 described previously, when the centrifugal separator 200 is rotated, so that a fluid can be more briskly flowed.

[36] In this case, the beads 400 collide with the raw material R in the middle of a space formed between the centrifugal separator 200 and the casing 300 due to fluid flow caused by the second pins 210a disposed in the upper position and the second pins 210b disposed in the lower position so that a milling process can be performed.

[37] The raw material R that undergoes the milling process and the beads 400 are flowed into the space between an inside of the centrifugal separator 200 and the internal tube 100 through a lower portion of the centrifugal separator 200 separated from the bottom plate 340. In this case, since the first pins 110 are disposed in a spiral form along the rotation direction of the centrifugal separator 200, upward directivity is given to the raw material R and the beads 400. Only the raw material R that is milled to be less than a predetermined size through the screen 120 disposed on the outer circumferential surface of the internal tube 100, of the raw material R moved to an upper portion of the internal tube 100 and the beads 400 may be discharged into the material outlet 340a through the inside of the internal tube 100.

[38] Meanwhile, the beads 400 and the raw material R having a size greater than the predetermined size cannot be discharged into gaps formed in the screen 120 and thus are flowed into the space formed between the centrifugal separator 200 and the casing 300 through the bead discharge holes 230 formed in the edges of the top surface of the centrifugal separator 200.

[39] In this way, according to the one or more of the above embodiments, since the beads

400 can be forcibly discharged and circulated through the bead discharge holes 230 formed in the separate centrifugal separator 20, the screen 120 is not clogged, and circulation is smoothly performed so that a strong milling force can be transferred to the raw material R, and the beads 400 and the raw material R are easily separated from each other so that a milling or dispersion capability can be improved, productivity can be improved and a process time can be reduced. In addition, due to the second pins 210a and 210b disposed in upper and lower positions in an asymmetric spiral form, the beads 400 collide with the middle of the space formed between the centrifugal separator 200 and the casing 300. In addition, the beads 400 having a small size of about 0.05 mm can be used.

[40] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

[1] A stirred ball mill comprising: an internal tube which has a cylindrical shape and in which a screen through which a raw material having a size less than a predetermined size is passed is disposed on an outer circumferential surface of the internal tube; a plurality of first pins coupled to an outer circumferential surface of the internal tube; a cylindrical centrifugal separator comprising a coupling groove formed in a middle of a top surface of the centrifugal separator and a plurality of bead discharge holes formed in edges of the top surface of the centrifugal separator, a bottom surface of the centrifugal separator being opened so that the internal tube is inserted in the centrifugal separator; a plurality of second pins coupled to an outer circumferential surface of the centrifugal separator; a cylindrical casing comprising an insertion hole formed in a middle of a top surface of the casing and a material inlet arranged at one end of the casing, the internal tube and the centrifugal separator being inserted in an opened lower portion of the casing; a bottom plate coupled to the opened lower portion of the casing so as to close an inside of the casing and comprising a material outlet arranged in a middle of the bottom plate, a bottom end of the internal tube being fixed on a top surface of the bottom plate; a plurality of beads disposed to move in a space formed between the internal tube, the centrifugal separator, and the casing; a shaft inserted in the insertion hole and coupled to the coupling groove; and a sealing member sealing a space between the insertion hole and the shaft.

[2] The stirred ball mill of claim 1, wherein the centrifugal separator comprises: a circular disc forming a body of the centrifugal separator; and a centrifugal separation discharge disc which is coupled to an upper portion of the circular disc and in which the coupling groove and the plurality of bead discharge holes are formed.

[3] The stirred ball mill of claim 1, wherein the centrifugal separator is separated from the bottom plate.

[4] The stirred ball mill of claim 1, wherein the first pins are arranged so that a plurality of circular groups are formed on the outer circumferential surface of the internal tube along a horizontal line.

[5] The stirred ball mill of claim 1, wherein the first pins are arranged in a spiral form along a rotation direction of the centrifugal separator so as to give upward directivity to the beads.

[6] The stirred ball mill of claim 1, wherein the second pins are arranged in a spiral form along the rotation direction of the centrifugal separator so as to give downward directivity to the beads when the centrifugal separator is rotated.

[7] The stirred ball mill of claim 1, wherein a plurality of second pins that are disposed in an upper position, of the second pins are disposed in a spiral form along the rotation direction of the centrifugal separator so as to give downward directivity to the beads when the centrifugal separator is rotated, and a plurality of second pins that are disposed in a lower position, of the second pins are disposed in a spiral form along a direction opposite to the rotation direction of the centrifugal separator so as to give upward directivity to the beads when the centrifugal separator is rotated.

[8] The stirred ball mill of one of claims 1 to 7, further comprising a plurality of third pins coupled to an inner circumferential surface of the casing to cross the second pins so as to not collide with the second pins when the centrifugal separator is rotated.

[9] The stirred ball mill of claim 1, wherein the sealing member comprises a mechanical seal.

[10] The stirred ball mill of claim 1, further comprising a cooling jacket arranged at an outside of the casing so as to cool the casing.

[11] The stirred ball mill of claim 1, further comprising a driving member providing a driving force that is used to rotate the shaft.