Solid material comminution or disintegration – Apparatus – Including means applying fluid to material
Reexamination Certificate
1999-06-25
2001-05-01
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Apparatus
Including means applying fluid to material
C241S040000
Reexamination Certificate
active
06224004
ABSTRACT:
This application is based on Japanese Patent Application No. 10-182086 filed in Japan on Jun. 29, 1998, the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a mill, and more particularly to a fluid-energy jet mill that grinds coarse particles using high-velocity gas.
2. Description of Related Art
In general, a fluid-energy jet mill grinds coarse particles in a milling chamber using high-velocity gas expelled from multiple nozzles. The type of fluid-energy jet mill shown in
FIG. 7
in particular has conventionally been used in many cases. In this conventional fluid-energy jet mill, as shown in the drawing, the milling material is introduced into the milling chamber
3
via the feeder
4
, and high-velocity gas is expelled from the nozzles
5
into the center of the nonpartitioned milling chamber
3
. When this occurs, the streams of high-velocity gas expelled from the nozzles
5
collide with each other, which grinds the milling material. The ground particles of the milling material are then sorted by means of a particle classifier
2
located in the upper area of the milling chamber.
However, the conventional mill described above suffers from the problem of poor milling efficiency (milling capacity per unit time).
OBJECT AND SUMMARY
The object of the present invention is to provide an improved mill that eliminates the problem described above.
Another object of the present invention is to provide a mill that offers superior milling efficiency.
These objects are attained by means of a mill comprising:
a milling chamber;
an expelling device that expels high-velocity gas into the milling chamber to grind the milling material in a prescribed milling area;
a particle classifier that classifies the ground particles of the milling material and returns back into the milling chamber the particles that are not of the desired size, said particle classifier being located such that it faces the milling chamber; and
a partition that divides the milling chamber into a first guide path that guides the particles of the milling material that are ground at the milling area into the particle classifier and a second guide path that guides back into the milling area the ground particles of the milling material classified by the particle classifier as requiring further milling.
In such a mill, the expelling device may be situated such that it expels high-velocity gas into the center of the milling chamber. In this case, the mill may have multiple expelling devices so that the milling material may be ground by means of the collisions of streams of high velocity gas expelled from the multiple expelling devices into the center of the milling chamber. Further, such a mill may be equipped with a member against which the high-velocity gas expelled from the expelling devices collides, such that the milling material is ground by means of the collision between the high-velocity gas expelled from the expelling devices and the member.
In such a mill, the expelling device may be situated such that the high-velocity gas is expelled toward the surrounding wall of the milling chamber. In this case, the mill may be equipped with a member against which the high-velocity gas expelled from the expelling device collides, such that the milling material is ground through the collision between the high-velocity gas expelled from the expelling device and the member.
In such a mill, the expelling device may have an opening facing the second guide path such that the milling material received from the opening are expelled together with the high-velocity gas.
Such a mill may furthermore have a collecting member that collects the milling material and guides it to the opening of the expelling device.
These objects are also attained by means of a mill comprising:
a cylindrical milling chamber;
multiple nozzles that expel high-velocity gas into the center of the milling chamber, said multiple nozzles each having an opening that receives the milling material and grinding the milling material by expelling it together with the high-velocity gas;
a particle classifier that classifies the ground particles of the milling material and returns back into the milling chamber the particles that are not of the desired size, said particle classifier being located at the upper area of the milling chamber; and
a cylindrical partition that is situated inside the milling chamber such that its axis is essentially aligned along the axis of the milling chamber, wherein the ground particles of the milling material reach the particle classifier through the interior of the partition, and the ground particles classified by the particle classifier as requiring further milling are led to the nozzle openings passing outside the partition.
In such a mill, it is preferred for the partition to have an inner diameter that is one-half to two-thirds of the inner diameter of the milling chamber.
Such a mill may furthermore be equipped with a member against which the high-velocity gas expelled from the multiple nozzles collides.
Such a mill may furthermore be equipped with hoppers that collect the milling material and guide it to the nozzle openings.
These objects may furthermore be attained by means of a mill comprising:
a cylindrical milling chamber;
multiple nozzles that expel high-velocity gas toward the surrounding wall of the milling chamber, said multiple nozzles each having an opening that receives the milling material and grinding the milling material by expelling it together with the high-velocity gas;
a particle classifier that classifies the ground particles of the milling material and returns back into the milling chamber the particles that are not of the desired size, said particle classifier being located in the upper area of the milling chamber; and
a cylindrical partition that is situated inside the milling chamber such that its axis is essentially aligned along the axis of the milling chamber, wherein the ground particles of the milling material reach the particle classifier through the outside of the partition and the ground particles classified by the particle classifier as requiring further milling are led to the nozzle openings passing through the interior of the partition.
Such a mill may furthermore be equipped with members against which the high-velocity gas expelled from the multiple nozzles collides.
Such a mill may furthermore be equipped with hoppers that collect the milling material and guide it to the nozzle openings.
In the various forms of mill described above, it is best if the expelling devices, i.e., the nozzles, comprise Laval-type nozzles.
REFERENCES:
patent: 4219164 (1980-08-01), Taylor
patent: 4579288 (1986-04-01), McDermid et al.
patent: 4905918 (1990-03-01), Selles et al.
patent: 62-42753 (1987-02-01), None
Kato Hitoshi
Shimoda Toshihito
Yamashita Takeshi
Yoshida Hideyuki
McDermott & Will & Emery
Minolta Co. , Ltd.
Rosenbaum Mark
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