Granulator

Abstract

Apparatus for granulating materials, having fly knives on a vertical rotor which cooperate with vertical stationary knives within a cone-shaped cutting chamber, the rotor being spaced from the wall of the chamber a greater distance at the top thereof than at the bottom, so that the entrance at the top of the chamber for material is larger than the exit throat at the bottom of the chamber, and both the stationary and fly knives extend into the cutting chamber further at the top thereof than at the bottom.

Description

BACKGROUND OF THE INVENTION

The conventional granulator, particularly those found in the plastic industry, has a rotor mounted on a horizontal axis and a screen at the outlet of the cutting chamber, the screen preventing the granulated material from passing through until it has been reduced to the desired particle size. As long as the cut material cannot pass through the screen, it is automatically thrust by the action of the rotor into the cutting edges of the device again, until it has been chopped to the point that it will go through the screen.

This arrangement has been found to be unsatisfactory for many applications where the nature of the material is such that it tends to clog the holes in the screen, or for heat sensitive materials which cannot endure the attrition between the screen and the rotating elements.

Other pulverizing apparatus has been used in the past, where a rotor is mounted vertically and the machine has a wide entrance throat and a relatively small exit throat. Such machines, however, are not suitable for the granulating of many materials, particularly plastic, because the action of such machines is one of grinding or fracturing, rather than of cutting. As a result of this, any materials which are not friable cannot very well be comminuted in such machines. Materials which are heat-sensitive (such as thermoplastic) will be softened by the friction encountered, with the result of clogging the whole machine.

Many attempts have been made to solve these problems and obtain a machine so designed as to comminute material to a given particle size without the use of a screen, and also to comminute non-friable or heat-sensitive materials without plugging up the machine.

SUMMARY OF THE INVENTION

Briefly, the machine of the present invention is a vertical granulator comprising rotor carrying fly knives and mounted on a vertical axis, the envelope of the rotating edges of the fly knives forming in a preferred form, a truncated cone. The fly knives are mounted so that they project (generally radially) a considerable distance from the body of the rotor at the top portion thereof, and project less from the body of the rotor at the bottom portion thereof. Rotor and knives are positioned in a cutting chamber formed by an enclosing housing having an interior wall that forms, with the body of the rotor, said chamber. Stationary knives project from the wall into the cutting chamber sufficient distance so that their inner cutting edges are positioned in cooperative relationship with the cutting edges of the fly knives. In one species of the invention, both the fly knives and stationary knives project into the cutting chamber further at the top thereof than at the bottom.

Accordingly, among the several objects of the invention are the provision of a granulating apparatus in which a large entrance throat and small exit throat are provided.

Another object of the invention is the provision of granulating apparatus of the above class having a vertical rotor and vertical cutting chamber, and in which the spacing between the body of the rotor and the housing decreases progressively in a downward direction.

A further object of the invention is the provision of a granulating apparatus of the above class in which cut pieces are progressively reduced in size as they progress downwardly in the cutting chamber.

Still another object of the invention is the provision of a granulating apparatus of any of the above types, or combination thereof, in which provision is made to enable the cutting knives to make a large bite on material entering the apparatus, the size of the bite progressively becoming less as the material passes through the machine.

Yet another object of the invention is to provide granulating apparatus of the above classes in which the lower portion of the cutting chamber is so shaped as to provide a chamber in which uniform cutting action takes place in order to make more uniform the size of the cut pieces.

Other objects and advantages of the invention will be in part obvious, and in part pointed out hereinafter.

Accordingly, the invention comprises the elements and combinations of elements, features of construction, arrangements of parts, and manipulation of the apparatus all of which will be exemplified in the structures hereinafter set forth, and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawings, in which several of the various possible embodiments of the invention are illustrated:

FIG. 1 is an elevation, partly in section, of one embodiment of this invention;

FIG. 2 is an elevation of a portion of the FIG. 1 embodiment, partly in section;

FIG. 3 is a sectional plan view taken in the direction indicated by sight lines 3--3 on FIG. 2;

FIG. 4 is a sectional plan view taken in the direction of sight lines 4--4 on FIG. 2;

FIG. 5 is a sectional elevation of a portion of a second embodiment of this invention;

FIG. 6 is a sectional elevation of a portion of yet another embodiment of this invention;

FIG. 7 is an elevation, partly in section, of a preferred embodiment of this invention;

FIG. 8 is a plan view in section taken in the direction of sight lines 8--8 on FIG. 7; and

FIG. 9 is a plan view of the FIG. 7 embodiment, partly in section, taken in the direction of sight lines 9--9 on FIG. 7.

Throughout the drawings, similar reference characters indicate corresponding parts, and the dimensions of certain of the parts as shown may have been modified and/or exaggerated for the purposes of clarity of illustration and understanding of the invention.

Referring first to FIGS. 1-4 for a basic simple embodiment of the invention, in which the parts described below are made of steel or aluminum in accordance with conventional good machine design practice, there is illustrated a base 2 (having legs 3) on which is mounted a motor 4 (electric or hydraulic) and four upstanding knife-supporting steel members 6 which are spaced equidistantly from each other about a circle, and which have their lower ends welded or otherwise conventionally secured to the base 2. If desired, a different number of supports 6 may be used. Fastened as by welding, between the supports 6 are four sheet metal members 8 which are portions of a hollow truncated cone. Members 8, as thus fastened, together form a hollow inverted truncated cone or pyramid which constitutes the outer wall of the cutting chamber of the apparatus.

Mounted on each of the supporting members 6 is a pair of stationary knives 10 and 12, these knives being mounted flatly against the respective supports by means of the bolts 14, the bolts traversing suitable slots in the knives 10 and 12 so that each of the knives may be adjusted inwardly and outwardly with respect to fly knives described below. Each knife extends into the cutting chamber through suitable slots or relieved portions 20 of the members 8 where these join the supports 6.

It is to be noted that each of the inner edges 16 of the upright supports 6 extends inwardly toward the center of the apparatus more at the bottom than at the top. As a result of this, an envelope which would enscribe these edges would form a truncated cone. The purpose of this is to enable the knives 10 and 12 to be properly supported when they are positioned so that the envelope of their cutting edges also forms an inverted truncated cone or pyramid within the cutting chamber formed by members 8. (Hereinafter, the cutting chamber is referred to by numeral 18.)

Extending upwardly at the approximate center of cutting chamber 18 is a rotor 22 whose lower shaft 24 is mounted by suitable bearings 26 fastened in base 2. At the upper end of the wall members 8 there is mounted, for example as by welding, a cylindrical housing 28 which forms a hopper, the hopper being closed by a plate 30 which holds a bearing 32 for the upper shaft 34 of the rotor 24. An opening 36 is provided in the side of the hopper 28, and a suitable loading chute 38 is fastened to this opening to guide materials into hopper 28 and thus to the top of the cutting chamber 18.

Rotor 22 is provided with three lengthwise slots 39 in the peripheral surface thereof, and in these slots are suitably fastened, as by welding, the fly-knife support members 40. It will be noted that the support members 40 are tapered so that they project outwardly into the cutting chamber 18 further at the top portion 42 thereof than at the bottom portion 44.

Each of the outer edges of the supports 40 is milled to provide a shoulder or rabbet which seats therein the fly knives 46, these being fastened into the rabbets by means of the bolts 48 in conventional manner.

Each of the stationary knives 10 and 12 is adjusted so as to come in proper cutting cooperation with the corresponding edges of the fly knives 46. In the drawings, the respective edges are shown separated more than would be the case in practice. For most materials, the cutting edges are adjusted to be very close together, but not touching. It will be noted, that when this adjustment has been made, and because of the inward extension of both the fly knife supports 40 and the stationary knife supports 6, the cutting edges meet in the central region of the cutting chamber 18, defined by the wall 8 and the periphery of the rotor 22, the cutting chamber formed by these two surfaces being a truncated conical annulus converging downwardly. Thus, at the top of the cutting chamber the gap 54 between the wall 8 and the rotor 22 (this gap being called the entrance throat) is large; whereas at the bottom of the rotor, the gap 56 (exit throat) is quite small. However, a continuous cutting mechanism is provided for the whole length of this cutting chamber starting from the top of the rotor down to the bottom.

Mounted slidably on the shaft 34 is a weighted plunger 50, the function of which is to press downwardly the material which has been placed in the hopper 28 for granulating, and thus urge the material into the cutting chamber. Plunger 50 may be raised manually.

Mounted below the rotor and affixed to shaft 24 to turn therewith is a spinner plate 52 which receives granulated particles (as they emerge from the exit throat 56) and throws them into a chute 60 having an exit 62. To assist this, the plate is provided with the impellers 58.

The rotor 22 is driven by means of a pulley 64 fastened at its lower end, the pulley being driven by the motor 4 through suitable drive belts 66 trained thereon.

Operation is as follows: Weight 50 is raised and material to be granulated is put into the hopper 28. It falls into the entrance throat 54 of the machine and begins to be cut by the fly and stationary knives. Due to the large size of the entrance throat relatively large size materials can be inserted. Earlier, mention is made of the machine being useful for the granulating of plastic materials. This is advantageous, because in many instances the materials to be granulated are thermoplastic materials which are scrap materials from molding machines. Hitherto, it has been often necessary to break up these materials by hand in order to get them into conventional granulating machines which do not have the large entrance throat provided by this machine. Also, it is to be noted that because of the large entrance throat, the machine can be used to cut up materials such as tin cans, aluminum cans, and also all kinds of garbage such as might be found in the kitchen of a commercial restaurant. A machine of this invention has been tested for granulating beer cans and garbage, and has worked successfully.

As the material is granulated, it moves by gravity down the cutting chamber, and the knives cut it finer and finer. Finally, the granulated material emerges from the exit throat 56, falls on the plate 52, and is thrown out of the machine via the chute 60.

Turning now to FIG. 5, there is shown a portion of a second embodiment of the machine, this second embodiment having much of the construction of the machine shown in FIGS. 1-4. The difference between this FIG. 5 embodiment and the FIGS. 1-4 embodiment lies in the construction of the knives, the rotor and the outer wall sections. In the FIG. 5 embodiment, a rotor 70 is shown which can be supported as is the rotor 22 of the FIGS. 1-4 embodiment, that is, at the top and bottom by suitable bearings. At the lower end of the rotor 70, it is tapered as indicated in the drawing so that it converges downwardly as shown at numeral 72. The fly knives 74 are mounted, as are the knives of the FIGS. 1-4 embodiment, on suitable fins or supports which project from the rotor, and each of these knives has a single straight cutting edge as shown. (In this particular drawing, the support members for these fly knives are not shown, since they are within the skill of the art to construct in view of the teaching of this case in respect to the FIGS. 1-4 embodiment.) The knives project into the cutting chamber further at the top than at the bottom.

The cutting chamber of FIG. 5 is made by means of the sectional walls 76 which, as in the case of FIGS. 1-4 housing, extend downwardly as portions of a truncated inwardly convergent cone. However, the bottom portion 78 of each section is angled so as to be parallel to the surface of tapered portion 72. The stationary knives 80 are mounted on upright supports similar to those of the FIGS. 1-4 embodiment, and are adjusted thereon to bring their cutting edges into proper cutting position with respect to knives 74. Each knife 80 extends the full length of knives 74. Therefore, in this FIG. 5 embodiment there is provided a section indicated by letter A which is a uniform annular cutting chamber. Within this cutting chamber, as the material comes downward from the upper portions of the knives 74 and 80, the material is further cut to a substantial uniform fine size.

Referring now to FIG. 6, there is shown another embodiment, similar to that of FIG. 5, except that in this instance the rotor 82 is like the rotor in the FIGS. 1-4 embodiment, in that it is not tapered as is the rotor 70. The fly knives 46 (with their supports) are provided, as in the FIGS. 1-4 embodiment. So, also, the stationary knives 10 and their respective supports are provided as in the FIGS. 1-4 embodiment. However, additional fly and stationary knives 84 and 86, respectively, are provided, these knives being mounted on suitable supports projecting, respectively, from the rotor 82 and from the wall of the housing member 88. The bottom portion 90 of each housing section is angled so as to extend in a direction parallel to the axis of the rotor 82. As a result, there is provided in this embodiment a bottom cutting chamber of uniform width, within which any particles already comminuted in the upper portions of the entire structure, will be further cut into a substantially uniform size. As compared, to the FIG. 5 embodiment, however, each fly knife and each stationary knife is made in two pieces.

Referring now to FIGS. 7-9 for a preferred embodiment of the invention, in which the afore-described basic features will be found, the enclosure in this instance is provided by means of three stationary knife holders 94, 96 and 98 which are securely fastened to a base plate 100 as by bolting or by welding. For simplicity, welding is preferred. These plates are held in aligned position by a top retaining ring 101 fastened to the tops of the plates, fastening being done preferably by welding.

To provide a cutting chamber, three arcuate doors 102, 104 and 106 are provided, each door being a section of a truncated cone, and converging inwardly and downwardly just as do the sections 8 of the FIG. 1 embodiment. Each door is reinforced by horizontal and vertical ribs 108 and 110. Also, for rigidity, the top of each door is provided with the outwardly extending narrow flange 112, and the bottom has a corresponding flange or floor plate 114. The bottom flange 114 of each of the covers is adapted to slide smoothly on the base plate 100. Additional rigidity is given to the doors by providing at each vertical edge the lips 111, these being adapted to rest snugly against supports 94-98 when the doors are closed.

Each of the cover sections is provided at top and bottom with the bosses 116 of conventional nature which are bored to receive a rod or shaft 118, the shaft seating in suitably provided sockets or holes in the top ring 101 and the base plate 100. By this means each of the doors is adapted to be swung outwardly to permit access to the interior of the mechanism, as illustrated by the dotted lines 120 of FIGS. 8 and 9. When the covers are open, then not only can the interior of the apparatus be cleaned, but the knives can be inspected and adjusted since full visibility thereof is provided. The construction of the cover sections 102, 104 and 106 is extremely strong because of the bracing by the ribs 108, 110; by the top flange 112; the bottom plate 114; and the side lips 111.

As shown in FIGS. 8 and 9, to close the structure and form the inwardly converging conical cutting chamber, the cover sections are swung shut until their lipped edges 111 abut the respective upright stationary knife supports, as shown in full lines in FIG. 9. In the closed position, as shown in FIGS. 7 and 9, a simple fastening mechanism is provided, such as the illustrated hand screw arrangement 122, the screw thereof projecting through the edge of the upright rib 111 of each housing section and threading into a suitably provided threaded hole in the stationary knife support 94, 96 or 98 as the case may be. As indicated in FIG. 7, three such hand screws are provided for each cover. Thus, by means of the shaft 118 at one edge of each cover, and the hand wheels 122 at the other edge, each cover is securely held to its respective vertical knife supports.

It will be noted (see FIG. 7) that the bottom portions 124 of each of the conical cover sections are vertical so as to be parallel to the axis of the rotor of this embodiment, just as described for the FIG. 6 embodiment.

The bottom plate 100 is provided with an aperture through which extends the rotor 126, and the plate in turn is supported by three of its sides on a platform 103 by means of supporting spacers 105. The rotor is supported in suitable bearings 128 in platform 103, which is supported on table 130. The latter is mounted on legs 132, so that the table is raised above floor level. The legs 132 are not shown in full length, and in practice will be made of sufficient length to permit a container (not shown) to be placed under the exit spout 184. At the top of the rotor is provided an additional bearing 134, of conventional nature, which is provided with suitable dust seals 136 and 138. The top bearing is mounted in a spider 140, the outer rim 142 of which is seated in the top ring 102 and fastened therein by conventional means. Thus, material to be granulated can be inserted into the cutting chamber through the spaces between the legs of the spider.

The stationary knives 146 comprise elongated flat blade members which are clamped in rabbets (provided at the inner edges of the knife supports 94, 96 and 98) by means of the elongated clamping plates 148, the latter being forced against the knives to hold them in position by means of the bolts 150. Each of these stationary knives may be adjusted by loosening the bolts 150, and then moving the knife radially inwardly or outwardly until the proper engagement with the fly knife (described below) is obtained. In order to assist in the adjustment, there are provided at a plurality of positions along the length of the stationary knife supports, the holes 152, the inner ends of which are threaded and open into the rabbets which seat the knife blades, the holes being in alignment with the knife blade when it is clamped against the rabbet shoulder. Screwed into each of the holes is an adjusting screw 154, the inner end of which abuts the back of the knife. For each vertical knife support, there are three such adjusting screws. In order to adjust the knife, the clamping plates 148 are loosened slightly, and then the screws 154 are turned to move the respective stationary knife to its proper position. Bolts 150 are then tightened.

As described for the FIG. 6 embodiment, a set of short stationary knives 158 is provided together with adjusting screws 160. Also provided are clamping means like plates 148 and bolts 150, but shorter in length commensurate with the length of knives 158. Adjustment of these short stationary knives is made as in the case of the knives 146.

Rotor 126 is a cylindrical body having extending therefrom fly knive supports or fins 162 for the major fly knife lengths 164. As in the FIGS. 1-4 embodiment, these supports are welded into suitable slots cut in the rotor 126. At the top of the rotor the supports 162 extend an appreciable distance into the cutting chamber. Supports 162 slant inwardly toward the lower portion of the rotor as in the FIGS. 1-4 embodiment. (See FIG. 4) Mounted in rabbets formed in the outer edges of these rotors are the fly knives 164 which are fastened into the rabbets by means of the bolts 166.

In order to provide short fly knives to cooperate with the stationary knives 158, four slots 168 are cut in the bottom portion of the rotor, into which are bolted by means of the bolts 170 the short fly knife lengths 172.

The rotor 126 has a shaft 174 extending downwardly on which is mounted a pulley 176. Suitable belts 178 connect the shaft to a motor (not shown) for rotation in conventional manner.

Mounted on the shaft 174 is an impeller 180 as described for the FIG. 1 embodiment, and surrounding the impeller is the discharge chamber 182 which terminates in the downwardly extending chute 184.

The top or entry end of the feed hopper of this preferred embodiment is not shown, since it can take the form of construction shown in FIG. 1, if desired.

The operation of this preferred embodiment FIGS. 7-9 is the same as the other embodiments described above.

In view of the above it will be seen that the several objects of the invention are achieved and other advantageous results attained.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense, and it is also intended that the appended claims shall cover all such equivalent variations as come within the true spirit and scope of the invention.

Claims

Having described the invention, what is claimed is:

1. Apparatus for granulating material comprising:

a rotor vertically mounted on a base so as to rotate about a vertical axis, the rotor comprising an elongated body having top and bottom portions and having a peripheral surface, and including a plurality of fins extending outwardly from said surface;

a housing surrounding the rotor and having an interior wall, said wall and the periphery of the rotor defining a chamber adapted to receive material to be granulated;

a plurality of fly knives each one of which is supported by one of said fins and extending generally lengthwise thereof, each fly knife having a cutting edge and projecting outwardly from the periphery of the rotor and into said chamber;

a plurality of stationary knives mounted in generally upright positions on said housing and projecting into said chamber a distance sufficiently great to be in close cutting relationship to the cutting edges of the fly knives when the latter turn;

a plurality of upstanding plate members extending from said interior wall into said chamber, each plate member comprising a support for one of said stationary knives; and

the horizontal distance from said wall to said periphery being greater at the top of the rotor than it is at the bottom of the rotor.

2. The apparatus of claim 1 in which each of said fly knives has its cutting edge positioned outwardly from the periphery of said rotor a distance greater at said top portion than at said bottom portion.

3. Apparatus for granulating material comprising:

a rotor vertically mounted on a base so as to rotate about a vertical axis, the rotor comprising an elongated body having a major upper portion of its length in the form of a cylinder, and a minor bottom portion of its length in the form of a first inverted frustrum of a cone;

a housing surrounding the rotor and having an interior wall, said wall and the periphery of the rotor defining a chamber adapted to receive material to be granulated, said interior wall having a major portion of its upper length in the form of a second inverted frustrum of a hollow cone converging toward said cylinder, and having a minor portion of its length extending downwardly to form a third inverted frustrum of a hollow cone whose surface is parallel to the surface of said first inverted frustrum at the bottom end of said rotor; said upper portions of the cylinder and said wall forming a chamber having an entrance throat at the top greater in spacing from the wall to the cylinder along a radial direction than exists at the bottom, and the chamber formed between said first and third frustrums being a conical torus;

a plurality of fly knives carried by the rotor and extending generally lengthwise thereof, each fly knife having a cutting edge and projecting outwardly from the periphery of the rotor and into said chamber;

a plurality of stationary knives mounted in generally upright positions on said housing and projecting into said chamber a distance sufficiently great to be in close cutting relationship to the cutting edges of the fly knives when the latter turn; and

the horizontal distance from said wall to said periphery being greater at the top of the rotor than it is at the bottom of the rotor.

4. Apparatus for granulating material comprising:

a rotor vertically mounted on a base so as to rotate about a vertical axis, the rotor comprising an elongated body having top and bottom portions and having a periphery;

a housing surrounding the rotor and having an interior wall, said wall and the periphery of the rotor defining a chamber adapted to receive material to be granulated, said housing comprising a plurality of upstanding supports mounted on the base and spaced apart thereon with respect to each other; retaining means holding the upper ends of said supports in rigid spaced-apart relationship; and said wall comprises a plurality of closure leaves one of such leaves fitting between each pair of said supports with one edge of each of said leaves being pivoted to said base and to said retaining means whereby each leaf can be pivoted outwardly to expose the interior of said chamber; each of said closure leaves constituting a section of the surface of a truncated cone whereby, when said closure leaves and said upstanding supports are assembled together, said housing constitutes an inverted frustrum of a hollow cone, the assembly including fastening means for rigidly fastening said closure leaves laterally to said supports;

a plurality of fly knives carried by the rotor and extending generally lengthwise thereof, each fly knife having a cutting edge and projecting outwardly from the periphery of the rotor and into said chamber;

a plurality of stationary knives mounted in generally upright positions on said housing and projecting into said chamber a distance sufficiently great to be in close cutting relationship to the cutting edges of the fly knives when the latter turn; and

the horizontal distance from said wall to said periphery being greater at the top of the rotor than it is at the bottom of the rotor.

5. The apparatus of claim 4 in which each of said closure leaves is provided with reinforcing members extending outwardly from the outer surface thereof, and rotatable means mounted at the bottom of said rotor and adapted to throw by centrifugal force any comminuted material falling thereon from said housing.

6. The apparatus of claim 4 in which each of said supports mounts one of said stationary knives, each knife being slidable toward and away from said rotor, and each of said upstanding support means including adjusting means for adjusting the position of said stationary knives with respect to said rotor; and also including clamping means for clamping each knife in its adjusted position.

7. Apparatus for granulating material comprising:

a rotor vertically mounted on a base so as to rotate about a vertical axis, the rotor comprising an elongated body having top and bottom portions and having a periphery;

a housing surrounding the rotor and having an interior wall, said wall and the periphery of the rotor defining a chamber adapted to receive material to be granulated; said housing comprising a plurality of upstanding supports mounted on the base and spaced apart thereon with respect to each other; retaining means holding the upper ends of said supports in rigid spaced-apart relationship; and said wall comprising a plurality of closure leaves fitting between said supports and pivoted with respect to said base whereby each leaf can be pivoted outwardly to expose the interior of the chamber; each of said closure leaves constituting a section of the surface of a truncated cone whereby, when said closure leaves and said upstanding supports are assembled together, said housing constitutes an inverted frustrum of a hollow cone, the assembly including fastening means for rigidly fastening said closure leaves laterally to said supports.