Chemistry: physical processes – Physical processes – Agglomerating
Reexamination Certificate
1998-05-28
2002-10-15
Silverman, Stanley S. (Department: 1754)
Chemistry: physical processes
Physical processes
Agglomerating
C023S3130FB, C034S365000
Reexamination Certificate
active
06464737
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to a production method and system for granulating powdered material, and more particularly relates to a production method and system for efficiently granulating powdered material with uniform property and small specific volume using pulsating vibration air.
II. Prior Art
FIG. 12
shows a known fluidized layer granulation system.
The granulation system
101
is comprised of a granulation tank
102
, an air source
103
, such as a blower fan, a discharge fan
104
, heating means
105
, such as a heat exchanger, and spray means
106
such as a nozzle means, for spraying a binding solution.
A supply port
102
a
for introducing heated air is provided under the granulation tank
102
, the air source
103
is connected to the supply port
102
a
via a conduit pipe and the heating means
105
is provided between the supply port
102
a
and the air source
103
. When the air source
103
is driven to cause the heating means
105
also to drive, the air produced by the air source
103
is heated by the heating means
105
, the heated air is supplied into the granulation tank
102
from the supply port
102
a,
and the supplied air is blown up in the granulation tank.
A fluidization bed
107
is provided above the supply port
102
a
in the granulation tank
102
. Powdered material A stored in the granulation tank
102
is deposited on the fluidization bed
107
when air isn't supplied to the granulation tank
102
.
Whereas heated air is supplied from the supply port
102
a,
the powdered material A deposited on the fluidization bed
107
floats to be mixed with the air blown upward from the fluidization bed
107
and forms a fluidized layer following the increase of the wind speed of the supplied air.
Further, a discharge port
102
b
is provided on the top of the granulation tank
102
and the discharge fan
104
is connected to the port
102
b
via a conduit pipe. The air supplied to the granulation tank
102
is discharged to the outside by driving the fan
104
.
On the other hand, the spray means
106
for spraying a binding solution is provided in the granulation tank
102
and connected with an air source
108
storing pressurized air via an air supply pipe
109
, and further a tank
110
for storing a binding solution is connected via a binding solution supply pipe
111
. A control unit
112
for adjusting the spraying amount of the spray means
106
is interposed in the middle of the pipe
111
.
In
FIG. 12
, the numeral
113
relates to a bag filter for preventing the raw powdered material A, the granulating material or the granulated material from flowing out of the granulation tank
102
and the numeral
114
relates to a dust collecting filter for eliminating dust in the air supplied to the granulation tank
102
.
In order to granulate material utilizing the system
101
, the raw material A is stored in the granulation tank
102
. Heated air is supplied into the tank
102
by driving the air source
103
and the heating means
105
and simultaneously the discharge fan
104
is driven, whereby the raw material A placed on the fluidization bed
107
is caused to be blown up. The heated air with constant flow amount and constant pressure is always supplied into the tank
102
by controlling the driving force of the air source
103
and the discharge fan
104
so that a desired stable fluidized layer is formed in the tank
102
. Thereafter, air with a fixed pressure is supplied to the spray means
106
for spraying a binding solution from the air source
108
and simultaneously the control unit
112
is driven. A binding solution B is sprayed from a desired spray and makes a bridge of solution between particles of the raw material A. The particles of the raw material A suspended in the granulation tank
102
as a fluidized layer mixed with air are aggregated and the aggregated particles are dried to be grown as a granulated material.
In the prior granulation method mentioned above, the granulated material with uniform physical properties (particle diameter, particle shape, etc) can be produced when material is granulated by spraying a binding solution from the nozzle after a dilute fluidized layer is formed by supplying a large amount of heated air with constant pressure and constant amount into the granulation tank
102
.
It is known that an increased speed of the particles becomes fast when particles are granulated by spraying a binding solution from the nozzle after a high density fluidized layer is formed by reducing the amount of heated air supplied into the granulation tank
102
.
However, when material is granulated by means of the system
101
, the granulated material becomes porous and its specific volume increases and becomes large because it is made from the particles floating in the air. In order to solve this problem, a new granulation method has been proposed in JP-A-60-183030.
FIG. 13
is a partially cutaway sectional view of the system disclosed in JP-A-60-183030.
A granulation system
201
is further provided with a rotary vane
202
a
on the fluidization bed
107
and a driving motor
202
to rotate the rotary vane
202
a
below the bed
107
. Heated air is supplied into the granulation tank
102
and the motor
202
is driven to rotate the vane
202
a
when the material A stored in the tank
102
is granulated. The material A directly receives rotating power of the vane
202
a
so that the material is prevented due to agitation from becoming porous.
According to the system
101
shown in
FIG. 12
, granulated material with a constant properties (particle diameter, particle shape, etc) is produced when material is granulated in a dilute fluidized layer by supplying a large amount of heated air into the granulation tank
102
. However, in the prior art, the concentration of the material A in a fluidized layer is dense and the particles of the material A do not doesn't have sufficient opportunity to touch each other so that particle growth becomes slow affecting the productivity of granulation.
Further, when a high density fluidized layer is formed in the granulation tank
102
by reducing the amount of the heated air supplied to the granulation tank
102
, each particle of the material A comes collides frequently, so that the particle growth of particle becomes fast. However, the particle diameter of the granulated material doesn't become uniform or projected parts like an antenna of a snail are formed on the surface of the particles so that granulated material with an irregular shape (not spherical) and different diameter is produced. Therefore, the system
101
can't be used when spherical granulated material is required. Furthermore, as mentioned above, the granulated material tends to be porous because the granulation is executed in air. As the result, it is difficult to produce granulated material with small specific volume.
When heated air is supplied at a uniform rate into the granulation tank
102
, the air may blow through a part of the material A placed on the fluidization bed
107
. In this case some of the material A in the tank
102
remains still and isn't fluidized. Granulated material isn't made from such a material, therefore, and the amount of granulated material becomes less compared to the amount of raw material A.
Slacking, bubbling or chanelling of the material A, which stop fluidization, may be caused in the granulation tank
102
while the material is granulated. The particle diameter, particle shape, density, and hardness of the granulated material depend on the fluidized condition of the raw material A and the granulating material.
Further in the prior art, unintended fine particles may be included in the granulated material. It is desired to reduce the amount of such fine particles. When the system
201
shown in
FIG. 13
is used, the granulated material is prevented from being porous because the rotary agitation flow by means of the rotation of the vane
202
a.
However, it is required to provide the rotary vane
202
a
Morimoto Kiyoshi
Murata Kazue
Tada Hiroshi
Tokuno Sanji
Yoshimoto Hirokazu
Jones Tullar & Cooper P.C.
Kyowa Hakko Kogyo Co. Ltd.
Silverman Stanley S.
Strickland Jonas N.
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