JPH06320035A - Conical ball mill - Google Patents

Abstract

PURPOSE:To provide a compact conical ball mill excellent in pulverizing effect and high productivity. CONSTITUTION:A rotary drum 11 in which a cylindrical body 11A and casing bodies 11B having the form of a truncated cone are provided successively with both the right and left ends of it connected to the bottom sides of them to form, and plural ribs 15 having about the shape of a V fixed to the internal wall of the cylindrical body 11A are provided. The centerline of rotation of the rotary drum 11 is horizontally set and the high speed rotation and the rapid damping of the drum 11 are repeated, causing a mixed body of a raw material 14 and a pulverizing medium to be accumulate along the internal wall of the cylindrical body 11A by centrifugal force applied on the high speed rotation. And the accumulated mixed body is diffused into the casing bodies 11B in the form of a truncated cone along the ribs 15 by inertial force applied to the rapid damping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conical ball mill in which raw materials such as ore, ceramic raw materials, chemical raw materials and a large number of ball-shaped grinding media are placed in a conical rotary drum, and the raw materials are ground by rotating the drum.

[0002]

2. Description of the Related Art A known conical ball mill is equipped with a rotary drum in which a part of a cylinder is formed in a truncated cone shape. According to this type of ball mill, when the raw material and a large number of ball-shaped grinding media are put in the drum, the rotation center line is set horizontally, and the drum is rotated, the grinding media roll on the inclined surface of the raw material and As it slides inside the deposit, the material between the grinding media is ground by friction. At the same time, the grinding medium rises along the inner wall of the drum due to centrifugal force and frictional force, and when it rises to a certain height, it falls off the inner wall from the middle due to gravity and falls to the bottom of the drum, and the impact force at this time crushes the raw material. It

[0003]

In the above-mentioned known conical ball mill, if the diameter of the rotary drum is increased so that the grinding medium rises to a high position, the grinding effect due to the impact when the grinding medium falls is enhanced. You can Also,
By increasing the rotation speed of the rotary drum to increase the kinetic energy of the grinding medium, the grinding effect due to friction can be enhanced. However, an increase in the diameter of the rotary drum inevitably leads to an increase in the size of the entire apparatus and an increase in power consumption, resulting in low productivity. When the rotation speed exceeds a certain level, the centrifugal force overcomes the gravity, so that the raw material and the grinding medium accumulated on the inner wall of the rotating drum rotate integrally with the drum while being pressed against the inner wall. Therefore, dropping and friction do not occur, and the crushing effect cannot be obtained at all. Therefore, there is a limit to the improvement of the crushing effect by increasing the rotation speed of the rotary drum to increase the kinetic energy of the crushing medium. The present invention has been made in view of such problems, and an object thereof is to provide a conical ball mill that is small in size, has an excellent crushing effect, and has high productivity.

[0004]

A conical ball mill according to the present invention comprises a rotating drum formed by connecting the bottom side of a cylindrical body having a truncated cone shape to the left and right ends of the cylindrical body, and a plurality of rotary drums fixed to the inner wall of the cylindrical body. By equipping the book with a substantially V-shaped rib, the center line of rotation of the rotating drum is set horizontally, and high-speed rotation and sudden braking of the drum are repeated, the mixture of the raw material and the grinding medium is aforesaid due to the centrifugal force acting at the time of high-speed rotation. It is characterized in that the mixture is deposited along the inner wall of the cylindrical body, and the deposited mixture is diffused along the rib into the cylindrical body of the truncated cone shape by the inertial force acting at the time of sudden braking.

[0005]

When the drum is rotated at a high speed, centrifugal force acts on the mixture of the raw material and the grinding medium, and the mixture accumulates along the peripheral wall of the cylindrical portion having the largest diameter among the various portions of the rotating drum. It then rotates together with the rotating drum. When the rotating drum rotating at high speed is suddenly braked and stopped, the mixture accumulated along the inner wall of the cylindrical body continues to rotate due to the inertial force with respect to the stopped rotating drum, so that it follows the substantially V-shaped rib. Scatter into the truncated cone. Since the diameter of the inner wall of the cylindrical body is smaller toward the end, the mixture is scattered along the inner wall of the cylindrical body while increasing the speed and is scattered toward the tip side of the cylindrical body. The raw material is crushed by friction as it scatters along the inner wall of the cylinder with the crushing medium. The inertial force that acts on the grinding medium when the rotating drum is stopped suddenly is proportional to the square of the number of revolutions.Therefore, increasing the rotational speed of the rotating drum increases the kinetic energy of the grinding medium and causes friction. The crushing effect can be enhanced and the crushing area by the ball mill can be expanded to ultrafine crushing.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
5 to 5, a ball mill 10 according to an embodiment of the present invention.
It is shown. The ball mill 10 includes a rotating drum 11
Is equipped with. This rotary drum 11 is formed by connecting the bottom side of a cylindrical body 11B having a truncated cone shape to the left and right end surfaces of the cylindrical body 11A, and the cylindrical body 11A is provided with an opening that can be opened and closed with a lid 12 from the opening. Ball-shaped grinding medium 13
The raw material 14 can be charged. Further, eight ribs 15 having a substantially V shape are fixed to the inner wall of the cylindrical body 11A.
The ribs 15 are arranged at equal angular intervals on the inner wall of the cylindrical body 11A so that each side expands toward the cylindrical body 11B side.
Shafts 16 are concentrically fixed to the left and right ends of the rotary drum 11, and are supported by bearings 17 so that the rotation center line of the rotary drum 11 is horizontal. Since the one shaft 16 is connected to the servo motor 18, high-speed rotational driving and rapid braking of the rotary drum 11 can be repeated in a short cycle.

This embodiment has the above structure, and its operation will be described with reference to FIGS. 3 to 5. FIG. 3 shows a state in which the rotary drum 11 is stopped. At this time, the mixture of the grinding medium 13 and the raw material 14 is deposited along the lower portion of the rotary drum 11. FIG. 4 shows a state in which the rotary drum 11 is rotating at a high speed by the servo motor 18. Centrifugal force acts on the grinding medium 13 and the raw material 14, and the rotating drum 1
The rotary drum 11 is integrated along the inner wall of the cylindrical body portion 11A having the largest diameter among the respective parts of 1 and is pressed against the inner wall.
Rotates together with. FIG. 5 shows a state in which the servo motor 18 is suddenly stopped and the rotating drum 11 is suddenly braked and stopped. Even if the rotating drum 11 stops and the centrifugal force disappears, an inertial force acts on the mixture of the raw material 14 and the grinding medium 13, and the rotating drum 11 continues to rotate with respect to the stopped rotating drum 11. Since the cylindrical body 11A of the rotary drum 11 is provided with the substantially V-shaped rib 15, the mixture is scattered along the rib 15 into the cylindrical body 1 or B. Since the diameter of the inner wall of the cylindrical body 11B becomes smaller toward the end, the mixture increases in speed and the cylindrical body 11B
While rotating along the inner wall of B, it scatters toward the tip side. Raw material 1
4 is crushed by friction when scattered along the inner wall of the cylindrical body 11B together with the crushing medium 13. The raw material 14 is gradually pulverized into fine particles by repeating high-speed rotational driving of the rotary drum 11 and rapid braking in a constant cycle.

Since the inertial force acting on the crushing medium 13 when the rotating drum 11 is suddenly braked and stopped is proportional to the square of the number of revolutions, the crushing medium is increased by increasing the rotation speed of the rotating drum 11. It is possible to increase the kinetic energy of 13 to enhance the crushing effect by friction, and to extend the crushing area by the ball mill to ultrafine crushing. In this embodiment, the servo motor 1 is used as a means for repeating high-speed rotation driving and sudden braking of the rotary drum 11 in a constant cycle.
However, the present invention is not limited to this, and it is also possible to use, for example, a three-phase squirrel-cage induction motor, and perform a desired operation by combining three-phase sine wave vector control and regenerative braking control. Is.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a ball mill according to an embodiment of the present invention.

FIG. 2 is a central cross-sectional view of the ball mill.

FIG. 3 is an operation explanatory view of the ball mill.

FIG. 4 is an operation explanatory view of the ball mill.

FIG. 5 is an operation explanatory view of the ball mill.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Ball mill, 11 ... Rotating drum, 11A ... Cylindrical body, 11B ... Cone trapezoidal cylinder body, 12 ... Lid, 13 ... Ball-shaped grinding medium, 14 ... Raw material, 15 ... V-shaped rib, 16 ...
Shaft, 17 ... Bearing, 18 ... Servo motor.

Claims (1)

[Claims] 1. A rotary drum comprising: a rotary drum formed by connecting the bottom side of a cylinder having a truncated cone shape to the left and right ends of the cylinder, and a plurality of substantially V-shaped ribs fixed to the inner wall of the cylinder. By installing the rotation center line horizontally and repeating high-speed rotation and rapid braking of the drum, the mixture of the raw material and the grinding medium was accumulated along the inner wall of the cylindrical body by the centrifugal force acting at the time of high-speed rotation, and accumulated. A conical ball mill characterized in that the mixture is diffused along the rib into the truncated cone-shaped cylindrical body by an inertial force acting during sudden braking.