Solid material comminution or disintegration – Processes – By utilizing kinetic energy of projected or suspended material
Reexamination Certificate
2001-12-04
2004-06-08
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Processes
By utilizing kinetic energy of projected or suspended material
C241S018000, C241S057000, C241S284000, C427S213000
Reexamination Certificate
active
06745960
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a granulation processing technology of powder grains, and more particularly to a technology effective in the case of granulating spherical particles of medical supplies, foodstuffs and the like by a centrifugal tumbling granulating apparatus.
BACKGROUND ART
Conventionally, there have been many types of power grain granulating apparatuses, and granulation processing is performed by various methods such as a tumbling granulating method, an agitating granulating method, an extruding granulating method, a disintegration granulating method, a fluidized bed method or the like by using these apparatuses. Among these methods, the most optimum method of obtaining spherical or nearly spherical grains is the tumbling granulating method that granulates the powder during tumble. A tumbling granulating apparatus for performing this is roughly classified into the following two types. That is, there are a type of rotating a container body f formed in a drum shape, an oblique shape, an oblique cone shape or the like, and a type of disposing a rotating disk on a bottom portion of a cylindrical container and of tumbling powder grains thereon, for example, similarly to an apparatus that has been disclosed in Japanese Patent Publication No. 46-10878 or Japanese Patent Publication No. 46-22544.
The apparatus that is the type of rotating the container is mainly used in granulation of ores, fertilizers or the like, and generates relatively large particles existing within a wide range of a particle size distribution. On the other hand, the apparatus that is the type of rotating the disk is also called a centrifugal tumbling granulating apparatus (hereinafter denoted briefly by a CF apparatus), and gives particles centrifugal force caused by rotation of the rotating disk and thereby performs spherical granulation. Therefore, the apparatus of this type can obtain small granulated substances existing within a narrow range of the particle size distribution, and so is generally used in fields of medical supplies, foodstuffs or the like.
In the CF apparatus combining the cylindrical container and the rotating disk with each other, a narrow annular slit is formed between an inner wall of the cylindrical container and an outer edge portion of the rotating disk. The above-mentioned slit has a narrow width in order to prevent particles in the container from falling from the rotating disk, and can supply air thereto in a down to up directions. Further, in the CF apparatus, since the rotating disk is rotated during supply of air into this slit, the particles on the rotating disk is tumbled by using the centrifugal force and thereby performs the spherical granulation.
However, in the CF apparatus like this, since the slit formed around the rotating disk has a narrow width, flow amount of air (slit air) passing through the slit is small and so hardly contributes to drying of particles generated. Accordingly, the CF apparatus itself is poor in a capacity of drying, and the generated spherical particles are transferred to another drying device and thereby are dryly processed. That is, the generated particles are taken out of the CF apparatus, and are dried in another fluidized bed device or the like, and are formed into products. Therefore, the good spherical particles have been obtained, but there arises a problem of productivity. So, improvement thereof is desired.
Thereupon, as disclosed in Japanese Patent Publication No. 61-8736, Japanese Patent Laid-Open No. 62-65729, Japanese Patent Laid-Open No. 59-49838 or the like, a tumbling granulating apparatus combining a cylindrical container and a rotating disk with each other has been developed by adding a drying function thereto, and has recently been sold at markets as a multifunction type granulating coating apparatus. For example, a Spir-A-Flow (a trade name) or the like made at Freund Industrial Co, Ltd. is an example thereof. In the apparatus of this Spir-A-Flow, a ventilation portion is provided in a rotating disk, and air is introduced from a down direction of this ventilation portion, such that granulation and drying processings can be performed inside the same apparatus. That is, such the multifunction type apparatus can supply air from the above-mentioned ventilation portion along with or after the granulation processing, and thereby make the granulated substances drying. Therefore, since it is not necessary to transfer the generated substances to another drying device and to dry the generated substances, enhancement in the productivity thereof can be achieved.
On the other hand, besides the device in which the ventilation portion like this is formed, for example, a device, as disclosed in Japanese Patent Laid-Open No. 61-242628, has also been proposed such that a slit formed between a cylindrical container and a rotating disk has a wide width to increase flow amount of slit air. In this device, since powders are easy to fall from the slit in accordance with enlargement of the slit width, a slit portion is further provided with a powder fall prevention mechanism. In this apparatus, while the powders are prevented from falling from the slit portion by this mechanism, enhancement of the drying capacity is achieved by the slit air amount increased. Some of the multifunction type apparatuses described above are designed to improve the drying capacity by the slit air amount increased, too.
In these apparatuses, a fluidized layer can also be formed in the container by the increased amount of air or slit air supplied from the ventilation portion, so that it is possible to granulate particles of various shapes from heavy spherical particles to light amorphous particles. Moreover, the above-mentioned apparatuses can be used even in coating of particles, and so has widely used as multifunction type apparatuses capable of performing various granulating coating processings.
However, in manufacture of spherical particles which have small deviation from spherical form and exist within a narrow range of the particle size distribution, researches of inventors have discovered that properties of granulated substances obtained by these multifunction type apparatuses are inferior to properties of granulated substances obtained by the CF apparatus having no drying function. Recently, in particular, spherical particles that each have a small size and exist within a narrow range of the particle size distribution have been demanded in pharmaceutical manufacture. However, since such granulated substances can not be manufactured by the above-mentioned multifunction type apparatuses, improvement thereof has been required.
In the multifunction type apparatuses described above, since powder grains are subject to buoyancy by air passing through the ventilation portion or the like and is not affected by sufficient tumbling action and compressing action, the inventors have surmised that properties of granulated substances are not improved. To avoid this, however, if the circulating air amount is decreased, then powder grains can not be prevented from falling from the ventilation portion or the like and drying capacity thereof is degenerated. Therefore, it is necessary to secure the air circulating amount equal to or more than a certain volume, and properties of granulated substances can not avoid lowering in comparison with those manufactured by the CF apparatuses having no drying function.
Further, in the conventional CF apparatus, properties of granulated subjects obtained are good, but a drying function is provided therein, and so it takes time and labor to transfer the granulated subjects to another drying device as described above, and a problem of productivity thereof has not been solved.
In
FIG. 5
disclosed in Japanese Patent Publication No. 46-10878 or FIG.
2
and
FIG. 3
disclosed in Japanese Patent Publication No. 46-22544, an apparatus has been proposed in which an air suction port is provided in an upper space of a centrifugal tumbling granulating apparatus. However, even if the air suction port is provided at a position re
Iwasaki Akira
Myo Nagayoshi
Nagaoka Koji
Okada Hiroshi
Shiratori Mamoru
Freund Industrial Co. Ltd.
McCormick Paulding & Huber LLP
Rosenbaum Mark
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