EP0451290A1

EP0451290A1 - Vibration grinding classifier

Info

Publication number: EP0451290A1
Application number: EP90915824A
Authority: EP
Inventors: Terumi Sasaki
Original assignee: KANSAI ZYARI KK
Current assignee: KANSAI ZYARI KK
Priority date: 1989-10-31
Filing date: 1990-10-26
Publication date: 1991-10-16
Also published as: EP0451290A4; AU6609090A; WO1991006370A1; JPH03146181A

Abstract

A vibration grinding classifier for a mineral material, which is simple in construction, compact in size and capable of offering a satisfactory classifying accuracy. This classifier is provided with a vibration motor (3) for oscillating grinding media in an annular vibration tank (1) containing therein a multitude of grinding media for grinding a powdery material (P) and a supply opening for the material (P). The lower part of the tank (1) serves as a grinding chamber (1a) in which the opening width in the radial direction is progressively increased from the bottom upward. The bottom plate of the grinding chamber is provided with a multitude of perforations (4a) for feeding air, which communicate with an air opening (4) for a classifying gas. The upper part of the tank (1) acts as a classifying chamber (1b) extending upwardly with the same opening width as that at the top end of the grinding chamber maintained. The top of the classifying chamber is provided with a discharge opening (7) through which a ground article of an intended particle size or below is discharged together with the classifying gas blown up through the perforations (4a).

Description

TECHNICAL FIELD

This invention relates to a vibration mill with a classifier which is used to mill, pulverize, or grind material such as mineral powder material and to classify the milled, pulverized or ground material.

TECHNICAL BACKGROUND

In prior art, mills such as an impact mill for milling material by a high-speed rotatable impact plate thereof and a vibration mill for milling material therein by vibrating a grinding medium such as a rod were used. The milled material only having a desired particle size was classified by a classifier which is separated from the mill.
The classifier for performing the above-mentioned classification is known as, for example, a centrifugal classifier. The centrifugal classifier is designed that its container for storing the milled material can be rotated at a high speed so as to classify the milled material therein into coase particles and fine particles by the effect of the centrifugal force.
However, as both the mill and the classifier separated from the mill are required to perform the above-mentioned milling and classification operations, it is a disadvantage to be large in size and complex in construction.
In addition, the classifier including the container is large in size and complex in construction, because the container must be rotated at a high speed. Furthermore, the milled material in a floc-state can not be surely classfied and thus it is impossible to perform the clasification in a highly precise manner. As the milled material is located on the inner face of the container by the effect of the centrifugal force, the inner face is quickly worn and thus the maintenance cost for exchanging the used container to a new container is high.

DISCLOSURE OF THE INVENTION

This invention is accomplished to solve the above-mentioned problems of the prior art. According to the first object of the invention, it is to develop a vibration mill with a classifier which can be constructed in a simple manner and be compact in size, and can perform classification operation in a sufficient precise manner.
According to the second object of the invention, it is to provide a vibration mill with a classifier wherein milling and classification operations can be performed in a highly efficent manner.
In order to accomplish the first object, a vibration mill with a classifier is characterized by comprising: a vibration container for storing many grinding media for milling powder material, the vibration container being formed in an annular shape; the vibration container provided with a vibration motor for vibrating the grinding media, the vibration container having a supply port for suplying the powder material; the vibration container in which a lower portion thereof employs as a milling chamber gradually upwardly widened in a radial width of the milling chamber; the vibration container in which an upper portion thereof employs as a classification chamber defined by an upwardly extending portion having a constant radial width equal to the radial width of the upper portion of the milling chamber; the milling chamber in which a bottom plate of the milling chamber is provided with many gas supply small openings for supplying classification gas into the milling chamber which are communicated to a classification gas supply port; and the classification chamber in which an upper portion of the classification chamber is provided with a discharge port for discharging the milled powder material having a particle size equal to or less than a desired particle size, together with the classification gas upwardly blowing through the gas supply openings from the classification chamber.
According to the above-mentioned construction, many milling or grinding mediums stored in the vibration container are vibrated by the vibration action of the vibration motor or motors.
The powder material is supplied through the supply port into the milling chamber. The supplied powder material is milled, ground or pulverized in a highly efficient manner by the impact and contact actions of the grinding mediums or grinding media. Furthermore, if the supplied powder material is in a floc state, the material can be milled, ground or pelverized in a highly efficient manner.
In addition, classification gas such as air is supplied through the gas supply small port from the bottom portion of the milling chamber. The classification gas A is supplied upwardly through the milling chamber 1a in such a manner that the flow velocity of the classification gas A is initially at a maximum and then gradually reduced, because the radial width of the milling chamber 1a is gradually upwardly widened from the bottom thereof. The classification gas upwardly blows at a constant minimum flow velocity in the classification chamber.
Accordingly, the classification gas a blows upwardly the powder material in the milling chamber. In this case, immediately the classification gas passes through the openings, the classification gas blows the powder material at the maximum flow velocity. The maximum flow velocity is set to apply an upwardly-blowing force greater than the gravitational force exerting on the powder material. The minimum flow velocity when reducing the flow velocity of the classification gas is set to apply the upwardly-blowing force of the fine powder having an average particle size equal to or smaller than the desired particle size. The fine powder of the powder material blowing at the minimum flow velocity upwardly passes through the classification chamber, and then the fine powder together with the classification gas is discharged from the discharge port. After that, the fine powder will be seperated from the classification gas.
As mentioned above, the powder material is milled while the fine particles are classified from coase particles. The classification gas blows upwardly the fine particles each having a particle size equal to or less than a desired particle size at the minimum flow velocity of the classification gas. But the classification gas can not blow upwardly the coase particles at the minimum flow velocity of the classification gas.
A vibration mill with a classifier of this invention is provided to accomplish the second object, wherein an annular vibration container is formed in a corrugated shape in its cross-section.
Therefore, the vibration container formed in the mentioned manner can transmit the vibration action thereof to the grinding mediums in a highly efficient manner. This leads the complex impact and contact actions of the grinding mediums for interaction. Thus, it is possible to reduce the particle size of the powder material and the milling and classification operations can be performed in a highly efficient manner.
Furthermore, in order to accomplish the second object, in a vibration mill with a classifier of this invention, the vibration container is provided with a baffle bar or bars, so as to forcedly transmit vibration action generated by the vibration container to the powder material.
Accordingly, as this leads the complex impact and cntact actions of the grinding medims, it is possible to reduce the particle size of the powder materials, so that the milling and classification operations can be performed in a highly efficient manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1 is a sectional view showing the whole of a first embodiment of a vibration mill with a classifier.
Fig.2 is a perspective view showing an interior structure of the first embodiment of the vibration mill with the classifier.
Fig.3 is a cross-sectional view showing the first embodiment of the vibration mill with the classifier.
Fig.4 is a plan view showing a vibration container of a second embodiment of the vibration mill with the classifier.
Fig.5 is a perspective view showing an interior structure of a third embodiment of the vibration mill with the classifier.
Fig.6 is an explanetory view showing vibration motors which are arranged in a different manner compared with vibration motors shown in Fig.1.

BEST MODE FOR CARRYING OUT THE INVENTION

EMBODIMENT 1

Figs.1 to 3 show a first embodiment of a vibration mill with a classifier. The structure of the vibration mill will be explained hereinafter.
In Figs. 1 to 3, a reference numeral 1 indicates a vibration container which has a large radially outer cylinder 10 and a small radially inner cylinder 11 to define an annular shape. The upper end of the vibration container 1 and the upper end of the inner cylinder 11 are closed by an upper plate 12. The bottom end of the vibration cotainer 1 and the bottom end of the inner cylinder 11 are also closed by a base plate 13.
In addition, the vibration container 1 is suspended or supported by means of coil springs 20 on a base 2 fixed on a floor so as to vibrate the vibration container 1. Two vibration motors 3, 3 are provided on the underside of the base plate 13. One vibration motor 3 meets face to face with other vibration motor 3 along the diameter direction of the vibration container 1. The rotation direction of the output shaft of one vibration motor 3 coincides with that of the output shaft of other vibration motor 3 from the viewpoint of the center of the vibration container 1.
In addition, the lower portion of the vibration container 1 employs as a milling chamber or grinding chamber 1a defined by inclined plates 14, 14 so as to gradually upwardly widen the radial width of the milling chamber 1a from the bottom thereof. The upper portion of the vibration container 1 employs as a classification chamber 1b which is defined by vertically extending portions of the outer and inner cylinders 10, 11 and has a constant radial width equal to the upper radial width of the milling chamber 1a. Many balls B as grinding mediums for material P to be ground, milled, or puluerized are stored within both the milling chamber 1a and the classification chamber 1b.
The bottom plate 15 of the milling chamber 1a is provided with many small gas supply-openings 4a so as to communicate the milling chamber 1a to a gas supply port 4.
Also, an end of a material supply pipe 60 which employs as a supply port 6 for the material P to be milled is connected to the milling chamber 1a. The supply port 6 is arranged immediately adjacent to the small hole 5a along a movement direction of the balls B. Incidentally, the pipe 60 for supplying the material to be milled has plural branch pipes 62 which connect an outer pipe 61 and connect through the outer cylinder 10 and the inclined plate 14 to the milling chamber 1a. The outer annular pipe 61 is connected to a supply cylinder 63 for supplying the powder material to be milled.
In addition, the upper portion of the classification chamber 1b is provided with discharge ports 7. The dischange ports 7 employ to discharge fine powder or pulverized powder P2 having a particle size equal to or less than the desired particle size of the material P to be milled, together with the classification gas A. The classification gas A is supplied via the small openings 4a to upwardly blow or transfer the fine powder P2. The discharge ports 7 are designed to be opened to the inner cylinder 11 along the inner circumference of the inner cylinder 11.
A recycling opening 8 for receiving the fine powder and a port 9 for discharging the classification gas A are communicated to the discharge port 7. The opening 8 is communicated to a recycling pipe 81 which extends from a hopper 80 of the lower side of the inner cylinder 11 through the inner cylinder 11 and outwardly projects over the outer cylinder 10. Also, the gas discharge port 9 passes through the upper portion of the inner cylinder 11 and the upper plate 12 and upwardly outwardly projects over. The gas discharge port 9 is surrounded by a guide cylinder 90 downwardly projecting from the inner face of the upper plate 12. Incidentally, the gas discharge port 9 is communicated to a dust collector or a cyclone and so on (not shown in Figures).

OPERATION

When synchronizing the vibration action generated by a pendulum of one vibrating motor 3 with the vibration action generated by a pendulum of the other vibrating motor 3 in both the vertical direction and the circumferential direction by operating the vibrating motors 3,3, the vibration container 1 produces the vibration action along the circumferential direction and the vertical vibration action. As a result, many balls B are vibrated and moved along the circular circumference direction within both the milling chamber 1a and the classification chamber 1b.
In addition, the powder material P supplied from the cylinder 63 for supplying the powder material P into the annular pipe 61 is moved along only one-way direction by a vibration action in a circular manner roughly along the circumference of the vibration container 1. The powder material P to be milled in the annular pipe 61 is supplied through the branch pipe 62 and the supply port 6 into the milling chamber 1a of the vibration container 1.
The powder material P within the milling chamber 1a in the above-mentioned manner is moved or transmitted together with the balls B, and milled, pulverized or ground by the impact and contact actions of the balls B against the powder material P. Furthermore, the floc of the powder material P can be surely milled. Incidentally, when the powder material P is downwardly supplied from the cylinder 63 into the annular pipe 61 and then moved or transmitted along only one way-direction by the vibrating movement of the vibration container 1, the powder material P is reduced to an average particle size in transmitting movement and then supplied through the supply port 6 into the milling chamber 1a.
In addition, the classification gas A such as air is supplied from the bottom portion of the milling chamber 1a via the gas supply small port 4a. The classification gas A is supplied upwardly through the milling chamber 1a in such a manner that the flow velocity of the classification gas A is initially at a maximum and then gradually reduced, because the radial width of the milling chamber 1a is gradually upwardly widened from the bottom thereof. After that, the classification gas A is supplied into the classification chamber 1b and goes upwardly through the classification chamber 1b at a constant minimum flow velocity.
Accordingly, the classification gas A blows or transmits the powder material P supplied into the milling chamber 1a. In this case, immediately after the classification gas A passes through the gas supply small openings 4a, the classification gas A blows or transmits the powder material P at the maximum flow velocity. The maximum flow velocity for the powder material must be set to apply the upwardly-blowing force of the powder material P greater than the gravitational force exerting on the powder material. The minimum flow velocity of the classification gas A in the milling chamber 1a must be set to obtain the upwardly-blowing force of the fine powder P2 having a particle size equal to or smaller than the desired particle size.
The fine powder P2 of the powder material P at the minumum flow velocity is upwardly blown or transmitted through the classification chamber 1b and then the fine powder P2 together with the classifcation gas A is discharged through the discharge ports 7. In this case, the discharged fine powder P2 with the classification gas A adheres to the inner circumference of the inner cylinder 11 and thus the fine powder P2 can be separated from the classification gas by the effect of the centrifugal force generated by the flow of the classification gas A, because the discharge ports 7 are provided along the inner circumference of the inner cylinder 11. The fine powder P2 separated form the classification gas A downwardly moves and then is collected by the hopper 80 and the collecting pipe 81. In addition, the classification gas A upwardly blows from the lower portion of the guide cylinder 90 to the center portion of the guide cylinder 90 and then is discharged through the gas exhausting port 9 to the outside.
In addition, the coase particles P1 of the powder material P which can not be upwardly moved at the minimum flow velocity remain in the milling chamber 1a. The milling operation for the coase particles are continuously performed until the coase particles are reduced to a particle size equal to or smaller than the desired particle size.

EMBODIMENT 2

Next, a second embodiment of the vibration mill with a classifier will be explained hereinafter referring to Fig.4.
In the second embodiment of the vibration mill with the classifier is characterized in that a vibration container 1 has an annular corrugated shape or space in a plan view defined by a large corrugated radial outer cylinder and a small corrugated radial inner cylinder. Incidentally, the construction of the second embodiment is similler to that of the first embodiment except that the secnd embodiment has the annular corrugated shape.
Therefore, in the vibration mill with the classifier according to the second embodiment, balls B are moved both along a lateral direction with respect to a circumferential direction and along the circumferential direction. The balls B are moved not only in the lateral direction but also in the circumference direction to lead complex impact and contact actions of the balls B against the powder material P to be milled. Thus, as the material P can be reduced to a fine particle size and the long total moving distance of the balls B the long total moving distance of and the powder material P can be obtain, the classification operation can be performed in a highly efficient manner.

EMBODIMENT 3

A third embodiment of the vibration mill with the classifier will be explained hereinafter, as shown in Fig.5.
The third embodiment of the vibration mill with the classifier is characterized by comprising baffle bars (baffle members) C for forcedly transmitting vibration action produced by the vibration container 1 to the balls B. Incidentally, as the third embodiment of Fig.5 is similar to the first embodiment of Fig. 1 except that the third embodiment has the baffle bars C, it needs no explanation for the third embodiment.
Accordingly, in the third embodiment, as the baffle bars C lead complex impact and contact actions of the balls B, the powder material can be reduced to a fine particle size and the milling and classification operations can be performed in a highly efficient manner.
This invention is not limited to the above-mentioned embodiments of Figures. All variations or modifications which come within the meaning of the claims are intended to be embraced therein.
For example, although the two vibration motors are used in the mentioned embodiments, the number of the vibration motors can be selected.
Each of the vibration motors can be also placed on a desired position, for example, as shown in Fig.6, the vibration motor 3 can be also set in such a manner that the axis of the output shaft of the vibration motor 3 is roughly parallel to a vertical direction. This particularly leads the advantage of no vertical-vibration motion. In addition, the number of the vibration motors can be optionally selected in this case.
Grinding medium may be optionally formed in a different shape or formed by a different material, for example, a metal grinding media or a ceramic grinding media may be used.
Also, the classification gas such nitrogen gas may be used.
As can be seen from the foregoing, according to the vibration mill with the classifier of this invention, as the vibration mill is provided with the annular vibration container or drum, milling operation of the powder material and separating operation of the fine particles from the coase particles, can be successively performed. Thus, the vibration mill with the classifier can be constructed in a simple manner and be compact in size. In addition, as the milling operation of the powder material is performed by the grinding medium and then the flow velocity of the classification gas can be reduced to the minimum value so as to upwardly blow the fine powder at the minimum flow velocity, the classification operation can be performed in a high precision.
In the vibration mill with the classifier according to this invention, as the vibration container is formed in the corrugated shape or space, the impact and contact actions or grinding medium such as balls increase in efficiency and thus milling and classification operations can be performed in a highly efficient manner.
Furthermore, according to the vibration mill with the classifier of this invention, as the vibration container is equiped within the baffle bars, the impact and contact actions of grinding medium such as the balls increase in efficiency and thus milling and classification operations can be performed in a highly efficient manner.

INDUSTRIAL FIELD

The vibration mill with the classfier of this invention is used for milling or grinding material such as mineral powder material and classifing the milled powder material.

Claims

A vibration mill with a classifier characterized by comprising:

a vibration container (1) for storing many grinding media for milling powder material (P), the vibration container (1) being formed in an annular shape;

the vibration container (1) provided with a vibration means (3) for vibrating the grinding media, the vibration container (11 having a supply port (6) for suplying the powder material (P);

the vibration container (1) in which a lower portion thereof employs as a milling chamber (1a) gradually upwardly widened in a radial width of the milling chamber (1a);

the vibration container (1) in which an upper portion thereof employs as a classification chamber (1b) defined by an upwardly extending portion having a constant radial width equal to the radial width of the upper portion of the milling chamber (1a);

the milling chamber (1a) in which a bottom portion of the milling chamber (1a) is provided with an opening (4a) for supplying classification gas (A) into the milling chamber (1a); and

the classification chamber (1b) in which an upper portion of the classification chamber (1b) is provided with a discharge port (7) for discharging milled material (P2) having a particle size equal to or less than a desired particle size, together with the classification gas (A) upwardly blowing through the opening (4a) from the classification chamber (1b).
A vibration mill with a classifier as set forth in claim 1 wherein the vibration container (1) is formed in an corrugated annular shape.
A vibration mill with a classifier as set forth in claim 1 or 2 wherein a baffle member (C) for forcedly transmitting vibration action of the vibration container (1) to the grinding media is provided within the vibration container (1).
A vibration mill with a classifier as set forth in claim 1 or 2 wherein the vibration container (1) comprises an outer cylinder (10) and an inner cylinder (11) in such a manner that the milling chamber (1a) and the classification chamber (1b) are defined between the outer cylinder (10) and the inner cylinder (11).
A vibration mill with a classifier as set forth in claim 1 or 2 wherein the vibration container (1) is supported by means of a spring (20) on a base (2).
A vibration mill with a classifier as set for in claim 1 or 2 wherein the grinding media (B) are stored in the milling chamber (1a) and the classification chamber (1b) of the vibration container (1), and wherein the classification gas (A) is upwardly blown from the milling chamber (1a) into the classification chamber (1b) so as to discharge the milled material (P2) having the size of particle equal to or less than a desired particle size.
A vibration mill with a classifier as set forth in claim 4 wherein a recycling means (8, 80, 81) for separating the milled material (P) having the particle size equal to or less than the desired particle size from the classification gas (A) and recycling the milled material (P) is provided within the inner cylinder (11).
A vibration mill with a classifier as set forth in claim 4 wherein the inner cylinder (11) is provided with an opening (9) so as to discharge the classification gas (A) from the inner cylinder (11) to the outside thereof.
A vibration mill with a classifier as set forth in claim 1 wherein the vibration means (3) is a vibration motor.
A vibration mill with a classifier as set forth in claim 9 wherein a plurality of the vibration motors are arranged relative to the vibration container (1) along the diameter direction of the vibration container (1).
A vibration mill with a classifier as set forth in claim 9 wherein the axis direction of the rotary shaft of the vibration motor (3) is roughly vertically directed.
A vibration mill with a classifier as set forth in claim 1 wherein the vibration container (1) comprises means (63, 61) for supplying the powder material (P).
A vibration mill with a classifier as set forth in claim 12 wherein the means for supplying the powder material (P) comprises a supply cylinder (63), an annular pipe (61) connected to the supply cylinder (63), and a branch pipe (62) connected to the annular pipe (61).
A vibration mill with a classifier as set forth in claim 13 wherein the annular pipe (61) is provided along the circumference of the vibration container (1).
A vibration mill with a classifier as set forth in claim 13 wherein the branch pipe (62) has the supply port (6) which is communicated to the milling chamber (1a).
A vibration mill with a classifier as set forth in claim 1 wherein the grinding medium (B) is a spherical grinding medium.
A vibration mill with a classifier as set forth in claim 4 wherein the discharge port (7) which is formed in the inner cylinder (11) is communicated to the classification chamber (1b) and the recycling means (8, 80, 81).
A vibration mill with a classifier as set forth in claim 3 wherein the baffle members (C) are arranged in radial direction.
A vibration mill with a classifier as set forth in claim 1, further comprising a gas supply means (41, 4) is provided to supply the classification gas (A) through the opening (4a) into the milling chamber (1a).