Plastic and nonmetallic article shaping or treating: processes – Formation of solid particulate material directly from molten... – Coated particles
Reexamination Certificate
2001-09-18
2004-02-24
Theisen, Mary Lynn (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Formation of solid particulate material directly from molten...
Coated particles
C264S014000, C425S006000
Reexamination Certificate
active
06695989
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for manufacturing granules including a spray nozzle disposed within a granulating chamber of an apparatus body for feeding by spraying into the granulating chamber a liquid material comprising at least one of mixture having solid and liquid in a mixed state and solution including solid dissolved therein, an air blowoff portion provided at a lower region of the granulating chamber for feeding air for floating and fluidizing the liquid material and fine particles under granulation inside the granulating chamber, and an air exhaust port provided at an upper region of the granulating chamber for exhausting the air present inside the granulating chamber. The invention relates also a method of manufacturing granules.
2. Description of the Prior Art
In the discussion to follow, the term “granules” refer to material obtained from fine primary particles by spraying the liquid material to them so that the particles have obtained somewhat increased diameter. The granules may be formed solid or may include a number of voids therein. Also, an aggregate of a plurality of such granules will be referred to hereinafter as a granular element. This granular element may be such that the individual granules are separated to be movable relative to each other or may be also a single agglomeration thereof.
Further, the term “primary particles” refer to seed particles for forming the granules. For instance, as described later herein, they refer to fine particles or the like which are formed when the sprayed liquid material is dried and solidified immediately after being sprayed from the spray nozzle.
SUMMARY OF THE INVENTION
An example of conventional granule manufacturing apparatus is disclosed in Japanese patent application “Kokai” No. Hei. 09-103668.
According to this apparatus, raw material particles serving as seeds for manufacturing granules are stored or charged in advance inside the granulating chamber. These raw material particles are fluidized by means of fluidizing air so as to form a fluidizing layer at a lower region of the granulating chamber Then, liquid material for granulation is sprayed downwardly and laterally from upper and lateral positions of this fluidizing layer to grow the raw material particles.
Specifically, as shown in
FIG. 22
, the raw material particles are stored at the bottom of the granulating chamber
1
. At this bottom, there is mounted a rotor
42
rotatable about a vertical shaft
44
. The rotor
42
defines a number of vent holes, through which fluidizing air
6
is supplied from under the rotor
42
to form an upwardly oriented air current inside the granulating chamber
1
, whereby the fluidizing layer R is formed immediately above the rotor
42
. To this fluidizing layer R, the liquid material
3
is sprayed from spray nozzles
4
disposed upwardly and laterally of the fluidizing layer R in directions opposed to and transverse the flow of the fluidizing air
6
, so as to grow the raw material particles to manufacture the granules.
However, when this conventional manufacturing apparatus is employed for manufacturing spherical and heavy granules with sharp size distribution, the following problems exist.
Namely, with the conventional manufacturing apparatus, it is necessary to prepare the raw material particles in advance inside the granulating chamber. In order to charge them into the granulating chamber to use them as raw material particles, certain conditions need to be satisfied, such as the particles should not be coagulated easily and the size distribution should be uniform. For this reason, the preparation of the raw material would tend to be troublesome, imposing a certain limit in improving the manufacturing efficiency of the granules.
Further, with the conventional manufacturing apparatus, the spray nozzle
4
for downwardly spraying the liquid material
3
is disposed at an upper position inside the granulating chamber
1
. And, this spray nozzle
4
sprays the liquid material
3
in the direction opposing the air
6
blown upward from the lower region of the granulating chamber
1
. The liquid material
3
, which is formed into fine droplets (mist) as the result of spraying, adheres to the raw material particles inside the fluidizing layer R to grow these raw material particles. However, in order to ensure that the downwardly sprayed liquid material
3
reaches the fluidizing layer R, it is necessary to limit the momentum of the upwardly directed air
6
to a certain extent. As a result, the space between the raw material particles inside the fluidizing layer R becomes insufficient, thus tending to invite coagulation of the raw material particles. For this reason, the granules obtained by using the conventional manufacturing apparatus tend to have a wide size distribution.
Moreover, the granules obtained by the above-described process tend to have a structure with many voids. Hence, it was difficult to obtain heavy granules.
Incidentally, another type of conventional apparatus includes a mechanism for intermittently blowing high-pressure air against the fluidizing layer R. For instance, the apparatus includes a plurality of jet nozzles
46
mounted along the periphery of the apparatus body
2
for discharging the air or gas against the fluidizing layer R. And, these respective nozzles
46
are mounted so that the gas discharging directions from all the nozzles will be focused at a single point within the fluidizing layer R.
Then, the particles inside the fluidizing layer R will blown by the high-pressure air currents toward the center of the granulating chamber
1
to collide against each other. This collision adds to the pulverizing effect of the counter jet mill, so that the granules tending to coagulate will be pulverized or cracked (hereinafter, “crushed”). Consequently, it becomes possible to render the particle diameters of the resultant granules uniform.
However, with the conventional manufacturing apparatus, the granules under granulation would coagulate easily. Hence, it was difficult to allow the above-described crushing effect to manifest itself effectively.
The present invention is intended to solve the above-described drawbacks of the conventional art and to provide a granule manufacturing apparatus and method capable of manufacturing spherical and heavy granules of a desired particle diameter in an efficient manner.
DISCLOSURE OF THE INVENTION
The characterizing features of the granule manufacturing apparatus and method relating to the present invention are as follows.
The granule manufacturing apparatus according to the present invention, as shown in
FIG. 1
, is characterized in that the spray nozzle is designed to spray the liquid material upwardly, the granulating chamber includes a cylindrical wall portion and a generally conical wall portion; the spray nozzle is disposed at a lower center region of the granulating chamber; the cylindrical wall portion is provided at a portion beside the nozzle; the nozzle includes a spraying opening which is located at a top or inwardly of a conical plane including the wall portion; and a bag filter is disposed between the spray nozzle and the air exhaust port, the bag filter having a backwashing unit, the bag filter providing the function of sweep-off means for sweeping off solids collected on the bag filter as well as the function of pressure applying means for momentarily increasing the pressure inside the granulating chamber.
If the liquid material is sprayed upward as proposed by the above construction, the spraying direction and the air supplying direction agree to each other. So that the spraying of the liquid material will proceed smoothly to ensure a sufficient floating period for the spray droplets of the liquid material. Thus, these spray droplets will be solidified completely to be formed into primary particles without coagulation with other primary particles. The effect of prevention of coagulation can be provided also during the subsequent process of the primary particles growing into
Hosokawa Micron Corp.
Theisen Mary Lynn
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
LandOfFree
Apparatus and method for manufacturing granules does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for manufacturing granules, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for manufacturing granules will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3319928