USRE27214E

USRE27214E - Method and apparatus for making spherical granules

Info

Publication number: USRE27214E
Authority: US
Priority date: 1968-05-31
Filing date: 1968-05-31
Publication date: 1971-11-02

Abstract

A METHOD OF AND APPARATUS FOR MAKING SPERICAL GRANULES FROM EXTRUSIONS OF A WET MIXTURE OF POWDERED SOLID MATERIAL BY INTRODUCING SUCH EXTRUSIONS ONTO A ROTATING CIRCULAR PLATE HAVING AN UNEVEN SURFACE. SUCH UNEVEN SURFACE PROPELS THE EXTRUSIONS OUTWARDLY BY CENTRIFUGAL FORCE AGAINST A STATIONARY WALL, THE EXTRUSIONS THEN FALLING BACK TOWARD THE CENTER OF THE ROTATING PLATE. SUCH REPETITIVE ACTION IS EFFECTIVE TO DIVIDE THE EXTRUSIONS INTO SHORT LENGTHS AND TRANSFORM SUCH LENGTHS INTO SUBSTANTIALLY UNIFORM SPHERICAL GRANULES.

Description

Nbv. 2,, 1971 NOBUO NAKAHARA 27,214

I METHOD AND APPARATUS FOR MAKING SPHERICAL GRANULES Original Filed June 17, 1964 3 Sheets-Sheet 1 HEEHE/ {NIKE/v70? Nosuo N msmm RA 5y mamFpww ek 2, 1971 NOBUO NAKAHARA Re- 27,214

METHOD AND APPARATUS FOR MAKING SPHERICAL GRANULES f- Oiiginill Filed June 17, 1964 3 Sheets-Sheet 2 i L :1 m" I Norauo NAHAHARA Nov. 2, 1971 Noauo NAKAHARA Re. 21,214

METHOD AND APPARATUS FOR MAKING SPHERIGAL GRANULES Original Filed June 17, 1964 3 Sheets-Sheet I NoBuo NRKAHARA Whsiliwwil%wma United States Patent 27,214 METHOD AND APPARATUS FOR MAKING SPHERICAL GRANULES Nobuo Nakahara, Matsubara, Japan, assignor to Fuji Denki Kogyo Kabushiki Kaisha, Garnaucho, Jotoku, Osaka, Japan Original No. 3,277,520, dated Oct. 11, 19,66, Ser. No. 375,904, June 17, 1964. Application for reissue May 31, 1968, Ser. No. 741,834

Int. Cl. B29c 23/00 US. Cl. 264-15 8 Claims Matter enclosed in heavy brackets II] appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE A method 07 and apparatus for making spherical granules from extrusions of a wet mixture of powdered solid material by introducing such extrusions onto a rotating circular plate having an uneven surface. Such uneven surface propels the extrusions outwardly by centrifugal force against a stationary wall, the extrusions then falling back toward the center of the rotating plate. Such repetitive action is efiective to divide the extru ions into short lengths and transform such lengths into substantially uniform spherical granules.

The present invention relates to a method and apparatus for making granules and particularly to methods and appparatuses available both for making spherical granules directly from wet mixtures of solids in powdered form and liquids, and for transforming wet granules in cylin drical, square and other irregular shapes which are made by granulators, screw type extruders and the like, into spherical granules.

In order to make spherical granules, the so-called pellets, it has been customary to use rotary drum type pelletizers, rotary pan type pelletizers and so forth.

In these machines, a drum or a pan rotates slowly into which material in powdered form is fed and rolled in accordance with the rotation of the drum or the pan and it is finally agglomerated to spherical granules by the addition of liquids which act as binding agents.

In these cases, .granules can be made on a relatively large scale, but strictly speaking, the granules obtained are not spherical and they are dilferent to a large extent in size and not uniform.

Accordingly, in order to obtain uniform size granules, screening process is absolutely required after the granulation or the pelleting.

Thus, it can be said that these methods and apparatuses or machines are not suitable for making spherical granules in uniform size, particularly for making small spherical granules in uniform size on a commercial basis.

In order to make spherical granules, a so-called pill making machine has been widely used in the pharmaceutical industry.

The machine can make rather correct spherical granules in uniform size, but it has only small capacity for its motive power and dimensions required and it cannot make small spherical granules having a diameter under 2.0 mm. clue to its mechanism.

Re. 27,214 Reissued Nov. 2, 1971 One of the objects of the present invention is to provide an apparatus for making small spherical granules in uniform size rapidly in batch system.

Another object of the invention is to provide the same apparatus operated in continuous system.

Other objects and advantages of the invention, including novel structural features, will be apparent from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is a sectional, side elevational view of the apparatus in accordance with the invention;

FIG. 2 is a plan view showing an example of an indented plate shown in FIG. 1;

FIG. 3 is a sectional, side elevational view of certain parts shown in FIG. 1, showing how material fiuidizes on the indented plate;

FIG. 4 is a plan view in horizontal section taken approximately on the line IVIV in FIG. 1, showing how the material travels on the indented plate along the inner surface of the wall of the casing;

FIG. 5 is a sectional, side elevational view of a second embodiment of the invention;

FIG. 6 is a plan view showing an example of the indented plates shown in FIG. 5; and

FIG. 7 is a sectional, side elevational view taken approximately on the line 11-11 in FIG. 6.

An embodiment of the invention is illustrated in FIGS. 1, 2, 3 and 4.

The apparatus, as shown in FIG. 1, comprises a base or frame 1 which may be supported at a convenient distance above the floor, a flat ring 2, and a vertical casing 3.

A rotor assembly is placed for rotation on a vertical axis in the casing 3 and the rotor assembly is driven by a vertical shaft 4 turning at high speed through a pulley 5 driven by a belt 6 from a separate drive motor, not shown.

The vertical shaft 4 is adapted to rotate within a ball bearing casing 7 which carries a ball bearing 8. The ball bearing 8 serves as the means for supporting the shaft 4.

The rotor assembly comprises an indented plate 9 which is keyed to the shaft 4 and fixed by a nut 10.

The indented plate 9 is positioned horizontally and its peripheral edge rotates adjacently to the inner surface of the wall of the casing 3.

And the indented plate 9 as best seen in FIG. 2 is round, flat and relatively thin, but provided with unevenness 9b on its peripheral upper surface with which material is in contact.

The unevenness 9b, in the present instance, is made by suitable crossing grooves and serves as the means for cutting and rubbing material.

An the unevenness 9b, as shown in FIG. 4, is attached by some suitable means like a bolt or binder, to-

the basic plate and it makes complete the indented plate 9.

The vertical casing 3 is shaped to cylindrical form to which a lip 11 is attached, the lip 11 being provided with a hopper 12.

A window 13 for discharge of material is provided on the side in the lower part of the casing 3 and positioned so that its lower edge may be approximately on the same level with the upper surface of the indented plate 9.

A cover 14 for the window 13 is attached to a handle 15 and the cover 14 is closed to the window 13 while treating material, but can be opened outwardly by an )perating assembly comprising the handle 15 when mate- 'ial is discharged.

A chute 16 is attached to the side wall of the vertical :asing 3 and it serves as the means for collecting dis- :harged material toward a suitable receptacle, not shown.

In operation, material is initially fed by hand, a vibratng feeder and other suitable means through the hopper [2 into the apparatus and then the material falls by gravity on the upper surface of the indented plate 9 which 'otates at high speed within the casing 3.

Next, the material on the plate 9, as shown by arrows n FIG. 3, is first thrown out by a centrifugal force caused :y the rotation of the plate 9 toward the periphery of the Jlate 9 and then it goes up along the inner surface of the vall of the casing 3.

And after the material loses the centrifugal force, it 'alls by gravity toward the center of the plate 9.

In FIG. 4, in accordance with the rotation of the plate I turning in the direction as shown by an arrow A, the naterial travels in the path of arrows B and it eddies dong the inner surface of the wall of the casing 3.

Accordingly, if cylindrical granules in random length IS material are fed to the apparatus, the granules are first :ut to uniform length, and rotated and revolved in the :asing 3 by the action of the unevenness 9b on the plate 9 1nd finally transformed into uniform spherical granules.

In this case, the cylindrical granules must be so made hat they have plasticity suitable for being transformed nto sphere before the treatment of the apparatus.

In order to make such cylindrical granules, liquids may Je added to the material in its granulation.

Further, if the plate 9 has no unevenness 9b on its upper :urface, the material cannot be cut or transformed into :pherical granules.

Therefore, it can be said that the unevenness 9b serves LS an important factor in the present apparatus.

'One of the features of the apparatus is that unexpected arge mass or granules are not produced because the mateial on the plate 9 is continuously thrown out radially Iiewed from the center of the plate 9 by a centrifugal force and each of cylindrical granules can be separated so as lot to be agglomerated.

If wet mixtures of solids in powered form and liquids as naterial are fed to the apparatus, the material is first dispersed radially and outwardly on the plate '9' and then by be same motion caused by the unevenness 9b of the plate as described in detail before, it can be granulated and tt the same time the granulated material can be further transformed into spherical granules of uniform size.

When the material is finished to spherical granules, the spherical granules can be discharged from the window 13 lesigned for the discharge of material by opening the :over 14 operated by the handle 15. The material may hen collect in a receptacle, not shown, through the chute ['6.

A second embodiment of the apparatus of the invenion is illustrated in FIGS. 5, 6 and 7.

In FIG. the apparatus comprises a casing, means for feeding material, means for discharging material and a rotor assembly.

The casing is composed of a vertical case 17 and nounted on a frame 18 which may be supported at a convenient distance above the floor.

The means for feeding material into the apparatus com- )rises a hopper 19, the hopper 19 being attached to a lip l0 placed at the top of the case 17.

The means for discharging material is composed of a vindow 21 for discharge of material, the window.21 being uositioned on the side in the lower part of the casing 17.

A chute 22 is attached to the window 21 so that the dis- :harged material can be smoothly collected into a suitable 'eceptacle, not shown.

A cover 23 is also attached to the window 21 and so 'ormed that the discharged material may overflow its lpper edge.

The rotor comprises a vertical shaft 24, special type indented plates 25, an indented plate 25b, covering plates 26, a fan 27, collars 28 and a nut 29.

The vertical shaft 24 rotates at high speed through a pulley driven by a belt from a separate drive motor, which is not shown, manner of which is similar to the one as shown in FIG. 1.

The special type indented plates 25 are composed of two pieces at least and three pieces in FIG. 5 and keyed to the shaft 24 so that they can rotate with the shaft 24.

Each of the three pieces of the plates 25 is round, flat and relatively thin as shown in FIG. 6 and provided with openings 30.

In the present instance, there are four of the openings 30 of each plate 25, the openings 30 being made to leave arms 33 between the center part 31 and the peripheral part 32 of the plate 25, as best seen in FIG. 6. The peripheral part 32 is provided with an uneveness similar to that at 9b of FIGURE 4 forming cross grooves in plate 25.

And these openings 30 serve as the hole of the droppage of the material.

The arms 33 are shaped to knife edges toward the direction of the rotation of the plate 25, as shown in FIG. 7.

In the present instance, the plate 25 rotates counterclockwise, as shown by an arrow in FIG. 6.

The knife edges are designed not to crush the material which is being granulated when it drops from the open- 1ngs'30.

Further, an indented plate 25b positioned in the lowest part is similar to the plate 9 in FIG. 2 and provided with no opening so that the material may not drop under the plate 25b. The plate 25b also causes the material to be exhausted smoothly from the discharged material window 21 by the centrifugal force of its rotation as described more fully hereinafter.

The covering plates 26 are composed of two pieces at least in the apparatus.

In the present instance, there are three of these plates 26 as shown in FIG. 5 and each of them is keyed to the shaft 24 so that it can rotate with the shaft 24.

These plates 26 are round, fiat and relatively thin and provided with no openings, diameters of which are approximately the same as the outside diameter of the openings 30 of the plate 25.

And these covering plates 26 are positioned over the corresponding plates 25 so that they can cover the openings 30, by which the material is first kept on the peripheral part 32 of the plate 25 and the material does not drop instantly from the openings 30.

The fan 27 is positioned under the lowest indented plate 25b and keyed to the shaft 24, and it rotates with the shaft 24.

This fan 27 is aimed to suck air from the lower part of the apparatus and to blow air up from the clearance between the peripheral edge of the plate 25b and the inner surface of the wall of the case 17 so that the material may not drop under the plate 25b and also not clog the inner surface of the wall of the case 17.

The collars 28 are composed of some pieces suitable for placing the fan 27, the special type indented plates 25, the indented plate 25b and the covering plates 26 at their right positions and all of them are easily detachable from the shaft 24.

The nut 29 is screwed into the top of the shaft 24 and it secures to the shaft 24 the covering plates 26, the special type indented plates 25, the indented plate 25b, and the fan 27 which are each rightly positioned by the collars 28 so that all of them can rotate together in accordance with the rotation of the shaft 24 and also can be easily detached from the shaft 24 by removal of the nut 29 for cleaning of the apparatus.

The operation of the second embodiment is, in principle, similar to that of the first embodiment shown in FIGS. 1, 2, 3 and 4; but it is featured by the fact that the second embodiment can be executed in continuous system, while the operation of the first embodiment is generally executed in batch system.

Accordingly, how the continuous operation is executed is explained hereunder.

If material is fed continuously to the apparatus, the material initially drops on the peripheral part 32 of the plate 25 at top position and begins to be made into spherical granules by the motion of the indented plate 25.

When the material becomes too much to be kept on the periphery 32, it begins to overflow the openings 30 of the plate 25 and drops on the periphery of the second position indented plate 25 by the aid of the next covering plate 26.

On the

third plates

25 and 26, the material goes through the same process as above.

But on the fourth indented plate 25h which is located in the lowest part, the material is exhausted to the chute 22 through the window 21 for discharge of material and is finally collected in a receptacle, not shown, by the aid of the centrifugal force caused by the rotation of the plate 25b.

The window 21 is provided with the cover 23 having suitable size to regulate the quantity of the discharged material.

It will thus be seen that the structure and operation of the apparatus and their methods have been fully described, and spherical granules can be made uniformly by the apparatus.

While two preferred embodiments of the invention have been illustrated by way of example in drawings and particularly described, it is to be understood that many different modifications and changes may be made without departing from the principles of the invention or the scope of the claims.

What is claimed is:

1. The spherical granule making apparatus comprising a vertical cylindrical casing having a hopper for feeding of material at its top and a window for discharge of material on its side in its lower part, a vertical shaft rotating in the casing, a plurality of plates having cross grooves fixed on the vertical shaft of which peripheral edges rotate adjacently to the inner surface of the wall of the casing, each of said plates having arms between a peripheral and center part forming openings for droppage of material, a plurality of covering plates which are round, flat and relatively thin, and positioned so that each of them may cover the openings of the corresponding plate, an indented plate which is positioned horizontally in the lowest part and on the same level with the lower edge of the window for discharge of material, peripheral edge of said indented plate rotating adjacently to the inner surface of the wall of the casing and a fan placed right under the lowest indented plate.

2. A spherical granule making apparatus of claim 1 in which the fan, placed right under the indented plate in the lowest part, feeds air from the lower part of the casing to the upper part of the casing.

3. The method of making spherical granules, com-prising the steps of forming extrusions of a wet mixture of powdered solid material, said extrusions having a maximum diameter proximating the desired diameter of the spherical granules,

introducing said extrusions onto a horizontal circular plate having an uneven peripheral upper surface and disposed with its peripheral edge adjacent to the inner surface of a surrounding stationary wall, in a limited quantity such that on rotation of the plate the material will be distributed in a ring on the outer portion of the plate adjacent the wall,

and rotating said plate at a high speed such that the uneven surface of the rotating plate propels the mate'- rial outward by centrifugal force against the stationary wall and upward along such wall, where the material loses its centrifugal force and falls by gravity back toward the center of the rotating plate,

and thereby efiecting a fluid flow of the material in a ring along the inner surface of the stationary wall, in repetitive eddies outward on the uneven surface of the plate, upward along the wall, and back toward the center of the plate,

the fluidized eddy flow so produced being effective to divide the extrusions into short lengths and transform such lengths into substantially uniform spherical granules.

4. The method of claim 3 in which said spherical granules are discharged by centrifugal force through an outlet of said stationary wall.

5. The method of claim 4 in which said extrusions are cylindrical.

6. The method of claim 5 in which said extrusions in said eddy flow repetitively travel from a point on said indented plate near its center across to its periphery.

7. The method of making spherical granules from nonspherical particles of a wet mixture of powdered solid material, starting with the particles in the form of extrusions or like bodies having a cross section with a maximum dimension proximating the desired diameter of the spehrical granules to be produced, comprising the steps f introducing the particles in said form onto a horizontal circular plate having an uneven peripheral upper surface and disposed with its peripheral edge adjacent to the inner surface of a surrounding stationary wall, in a limited quantity such that on rotation of the plate the material will be distributed in a ring on the outer portion of the plate adjacent the wall,

and rotating said plate at a high speed such that the uneven surface of the rotating plate propels the material outward by centrifugal force against the stationary wall and upward along such wall, where the material loses its centrifugal force and falls by gravity back toward the center of the rotating plate,

such fluidized eddy flow being effective to divide long particles and transform the material into substantially uniform spherical granules.

8. Apparatus for making spherical granules from non.- spherical particles of a wet mixture of powdered solid material, which particles are in the form of extrusions or like bodies having a cross section with a maximum dimension proximating the desired diameter of the spherical granules to be produced, comprising a stationary cylindrical wall defining a casing,

a horizontal circular plate mounted for rotation on a vertical axis with its pheripheral edge adjacent to the inner surface of said cylindrical wall, and adapted to support a ring of material on its outer portion adjacent said wall,

said plate having an uneven peripheral upper surface for contact with material being treated in the casing,

means to rotate such plate within said casing at a high speed sufficient to distribute the material on the plate in such a ring and to cause said uneven surface to propel material in contact with it outward by centrifugal force against said wall and upward along said wall to a level at which the material loses its centrifugal force and falls by gravity back toward the center of the plate,

such rotation thereby effecting a fluid flow of the material being treated in a ring along the inner surface of the wall and in repetitive eddies outward on the uneven surface of the plate, upward along the wall, and back toward the center of the plate,

the fluidized eddy flow so produced being effective to 7 8 divide elongated particles into short lengths and trans- 2,305,172 12/ 1942 Landgraf 18-26 X form the material into substantially uniform spherical 2,696,019 11/1954 Allan et a] 18-1 granules. 2,876,491 3/1959 Meyer 18-1 References Cited 2,929,107 3/1960 Andrew 1812 X The following references, cited by the Examiner, are 5 523; 5

1 7 zgtfifiord 1n the patented file ef th1s patent or the ongma 3,103700 9/1963 Halverson fit al- 8 1 X Ishimitsu et a1. 3, 8, 10/1966 Beck 1 AX 10 WILLIAM s. LAWSON, Primary Examiner 1,051,877" 4/1913 Gabbett-Fairfax 20987 X 1,915,201 6/1933 Ragg 18-26 X U.S. Cl. X.R. 2,120,540 6/1938 Billings et a1 23314 18-- 1 B; 264-117 2,120,541 6/1938 Billings et a1 233 14