JP3318402B2 - Pulverizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine pulverizer for mixing and pulverizing powder materials such as ceramics.

[0002]

2. Description of the Related Art In a ceramics manufacturing process, a raw material powder is pulverized to a predetermined particle size and various additives are mixed. In the mixing and pulverizing process, a ball mill, a tube mill, a compound mill, and the like are conventionally used. It is used. These pulverizers are used to pulverize a ceramic raw material by the impact of the balls by charging and rotating a large number of balls as a pulverizing medium together with the ceramic raw material, and are often used as a fine pulverizer having a large pulverizing ability.

[0003]

However, since these pulverizers perform pulverization in a state in which the pulverizing cylinder is closed, mixing,
There is a problem that gas components generated during the pulverization cannot be naturally exhausted from the pulverization cylinder.

In particular, when flammable gas such as ammonia or hydrogen is generated, in order to keep the concentration below the explosion limit constantly, it is necessary to stop the crusher during the crushing and mixing and to periodically perform a degassing operation. Work efficiency was poor.

The present applicant has already proposed a crusher using a prismatic crushing cylinder (see Japanese Patent Publication No. 4-24108), but this crusher also holds the crushing cylinder horizontally. It had no degassing function to rotate.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a pulverizing cylinder having a cylindrical central portion and a conical end at one end, and one end of the pulverizing cylinder having an open port. The gas is always released from the upper opening.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the pulverizer of the present invention comprises:
The grinding cylinder 1 is provided at the tip of a support shaft 2 rotatably mounted on the support base 3 in the vertical direction. The rotating disk 4 attached to the support shaft 2 is rotated by a motor 5 so that the inclination of the crushing cylinder 1 and the support shaft 2 with respect to the horizontal plane can be freely adjusted within a range of −50 to 90 °. Has become.

Although the detailed structure is not shown, the pulverizing cylinder 1 is configured to be rotatable around the center axis of the support shaft 2.

Further, as shown in FIG. 2 showing only the shape of the crushing cylinder 1, the crushing cylinder 1 is provided with a central prism 11 and a back pyramid 12 and a tip pyramid 13 continuous with the center prism. The side end 14 is closed, but the tip is an opening 15. Although not shown in the drawings, the crushing cylinder 1 may be provided with a lining of rubber, resin, ceramics, or the like.

When the fine pulverizer of the present invention is used, first, as shown in FIG. 3, the angle θ ₁ of the support shaft 2 with respect to the horizontal plane is set so that the opening 15 of the pulverizing cylinder 1 faces directly above. At 90 °, the raw material powder, the pulverizing medium and the like are introduced into the pulverizing cylinder 1.

Thereafter, as shown in FIG. 4, the support shaft 2 is held obliquely at an angle θ ₁ with respect to the horizontal plane with the opening 15 of the crushing cylinder 1 facing upward. Is rotated about the support shaft 2 to pulverize the raw material powder.

At this time, since the opening 15 is present in the pulverizing cylinder 1, the generated gas is released while the pulverizing is performed.
, And the mixing and pulverizing steps can be performed efficiently. The generated gas exhausted from the opening 15 is suctioned by a duct or the like and exhausted outside the room.

Further, since the crushing cylinder 1 is composed of a square cylinder and a pyramid, convection of balls and the like during crushing can be increased, and crushing efficiency can be increased. At this time, the surfaces that most contribute to the pulverization efficiency are the central prism 11, the rear pyramid 12, and the rear end 14. In particular, the central prism 11 and the rear end 14 each have an angle θ _{2 with} respect to the horizontal plane. , θ ₃ has a great influence.

The angles θ ₂ and θ ₃ are preferably in the range of 40 to 50 °. This is because when the angles θ ₂ and θ ₃ are smaller than 40 °, the internal convection is reduced and the pulverization efficiency is reduced. On the other hand, when the angles θ ₂ and θ ₃ are larger than 50 °, the internal This is because the effective volume for pulverization decreases, and the amount that can be pulverized at one time decreases. Since θ ₂ = θ ₁ θ ₃ = 90 ° −θ ₁ due to the structure of the pulverizer, in order to keep the angles θ ₂ and θ ₃ within the above range, θ ₁ must be 40 to 50 °. It may be within the range.

When used in the state shown in FIG. 4, the back pyramid surface 12 is the bottom surface. If this portion is too long, the pulverizing efficiency is reduced. The length is shorter than the length of the portion 11 and the tip-side pyramid portion 13.

On the other hand, in order to spontaneously release the generated gas, the upper portion of the pyramid portion 13 on the tip side has an angle θ with respect to the horizontal plane.
₄ must be greater than 0 °. That is, if the angle θ ₄ is less than the horizontal in the state shown in FIG. 3, a part of the generated gas may be confined in the crushing cylinder 1.

If the diameter of the opening 15 is too large, the pulverized material jumps out to the outside. Therefore, it is needless to say that the diameter of the opening 15 is balanced with the gas release.

After the completion of the pulverization, if the pulverizing cylinder 1 is turned downward by rotating the support shaft 2 as shown in FIG. 5, the pulverized material inside can be easily taken out.

In the above embodiment, the crushing cylinder 1 has a rectangular cylinder or a pyramid shape. However, the crushing cylinder 1 is not limited to this. For example, the crushing cylinder 1 has a cylindrical shape at the center and a conical shape at both ends. It may be. Further, it goes without saying that the pulverizer of the present invention is used not only for mixing and pulverization of ceramic raw materials but also for pulverization of various powders.

EXPERIMENTAL EXAMPLE 1 An experiment was conducted in which silicon nitride powder, a sintering aid, and water and silicon nitride balls were charged into a pulverizing cylinder 1 at a weight ratio of about 100: 12: 70: 250, and pulverized. . At this time,
In grinding silicon nitride, ammonia gas is generated by a chemical reaction of Si ₃ N ₄ + 6H ₂ O → 3SiO ₂ + 4NH ₃ .

The grinding time when the angle θ ₁ of the grinding cylinder 1 with respect to the horizontal plane at the time of grinding is changed in three ways of 55 °, 45 °, and 10 °, and the opening 15 is opened and rotated at 20 rpm. And the average particle size of silicon nitride and the ammonia concentration in the grinding cylinder 1 were measured. Table 1 shows the results
As shown in FIG. In addition, when the elapsed time and the ammonia concentration when each was pulverized for 120 hours and left as it was were measured, the results were as shown in Table 2.

[0023]

[Table 1]

[0024]

[Table 2]

From these results, it can be seen that θ ₁ is 55 ° and θ ₁
Is 10 °, the average particle size is 1.3 after grinding for 120 hours.
１．５1.5 μm, but θ ₁ was 45
In the case of °, it was possible to pulverize to an average particle diameter of 1.0 μm and a target particle diameter by grinding for 120 hours.

[0026] This is the angle theta ₃ angle theta ₂ and the rear end portion 14 of the central rectangular tube portion 11 in FIG. 4 is a problem. That is, when θ ₁ = 55 °, θ ₃ = 35 °, and θ ₁ =
In the case of 10 °, θ ₂ = 10 °, and the angle becomes smaller than the preferable range, so that the crushing efficiency decreases. On the other hand, in the case of θ ₁ = 45 °, θ ₂ = θ ₃ = 45 ° And the pulverization efficiency increases.

On the other hand, with respect to the ammonia concentration, it was confirmed that the slurry inside the crushing cylinder 1 was vigorously moved during the crushing and mixing, and the ammonia was forcibly exhausted from the crushing cylinder 1 through the opening 15. However, as shown in Table 2, when the pulverizing cylinder 1 is in a stationary state, there is no escape for gas, so that gas temporarily accumulates in the pulverizing cylinder 1 at θ ₁ = 10 °, whereas θ ₁ = 55 ° or θ
_{At 1} = 45 °, it was confirmed that the gas was exhausted and decreased.

The explosion limit of ammonia is usually 160
Although it is 2,000 to 250,000 ppm, it was confirmed that, when θ ₁ = 45 °, gas was constantly released, and a target average particle diameter of 1 μm could be obtained safely with respect to the ammonia concentration.

The crushing efficiency can be further improved by adjusting the rotation speed of the crushing cylinder 1, the ratio and size of the crushing balls, but the generation of gas accompanying the crushing becomes large. It is important to consider the safety level for the allowable concentration.

[0030]

As described above, according to the present invention, the tip of a crushing cylinder having a cylindrical central portion and a conical end is used as an open port, and the crushing cylinder is installed obliquely to finely crush the powder. Since the gas generator is configured to constantly release gas from the upper opening, mixing and pulverization of the gas generating substance can be performed easily and efficiently.

Furthermore, by making the angle of the crushing cylinder variable, the mixing and crushing operation can be simplified.

[Brief description of the drawings]

FIG. 1 is a side view of a fine pulverizer of the present invention in a state where a pulverizing cylinder is oriented in a horizontal direction.

FIG. 2A is a front view of a pulverizing cylinder used in the fine pulverizer of the present invention, and FIG. 2B is a sectional view taken along line XX in FIG.

FIG. 3 is a side view of the fine pulverizer of the present invention in a state where a pulverizing cylinder is directed right above.

FIG. 4 is a side view showing a use state of the pulverizer of the present invention.

FIG. 5 is a side view showing a state in which a pulverizing cylinder of the fine pulverizer of the present invention is directed downward.

[Explanation of symbols]

1: Crush cylinder 2: Support shaft 3: Support base 4: Rotating disk 5: Motor 11: Central square tube part 12: Back side pyramid part 13: Tip side pyramid part 14: Back side end part 15: Opening end θ ₁ : The angle of the support shaft 2 with respect to the horizontal plane θ ₂ : the angle of the central rectangular tube 11 with respect to the horizontal plane θ ₃ : the angle of the rear end 14 with respect to the horizontal plane

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B02C 17/00-17/24

Claims (1)

(57) [Claims] 1. A device which is rotatably mounted on a support base in a vertical direction.
A grinding cylinder is provided at the tip of the attached support shaft, and the grinding cylinder has a cylindrical central portion, both ends are cone-shaped, and the distal end portion is an opening, and the opening is upward. So that the grinding cylinder can be rotated around the center axis of the support shaft.
A fine pulverizer characterized by: