US2750120A

US2750120A - Impact process and apparatus for disintegrating materials

Info

Publication number: US2750120A
Application number: US339565A
Authority: US
Inventors: Pallmann Ludwig
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-03-02
Filing date: 1953-03-02
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 Filed March 2, 1953 L. PALLMANN 4 Sheets-Sheet .l

LUDWIG PALLMANN,

IN V EN TOR.

A T TORNEY.

IMPACT PROCESS AND APPARATUS FOR DISINTEGRATING MATERIALS Filed March 2, 1953 June 12, 1956 PALLMANN 4 Sheets-Sheet 5 LUDWIG PALLMANN INVENTOR.

A7'7ORNEK June 12, 1956 PALLMANN 2,750,120

IMPACT PROCESS AND APPARATUS FOR DISINTEGRATING MATERIALS Filed March 2, 1953 4 Sheets-Sheet 4 LUDWIG PALLMANN, y INVENTOR.

A TTORNEY,

United States Patent Ofiice llVIPACT PROCESS AND APPARATUS FOR DISINTEGRATIN G MATERIALS Ludwig Pallmann, Zweibrucken, Germany Application March 2, 1953, Serial No. 339,565 22 Claims. (Cl. 241-27) This invention relates to methods and devices for mechanically disintegrating materials into small particles and is directed to a process and a power driven device for carrying out the process that are universally adaptable in the sense that they may be applied to the problem of disintegrating .a Wide variety of materials, including materials that defy processing by conventional grinding devices and explosive materials that must be processed in spark-proof devices. This application is a continuation in part of my now abandoned copending application Serial Number 185,212, filed September 16, 1950, and entitled Process and a Device for Grinding Materials of all Kinds.

The invention has been used successfully in continuous mass production to reduce various Wet and dry materials to various degrees of fineness. Such diverse materials have been processed as Wood waste, lumber knots, rubber waste, textile waste, paper Waste, roots, peat, asbestos, resins, thermoplastics, bones, fruit, vegetables, meat, fish, as well as rocks and ores of various degrees of hardness and toughness. The invention accomplishes its purpose with such a Wide range of materials by causing the pieces of material to be subject to rapidly successive high velocity impacts against each other and against suitable impact surfaces. The invention preferably also provides progressively restricted processing zones and provides centrifugal force to cause the progressively diminishing pieces of material to migrate through these zones.

The preferred embodiments of the invention disclosed herein include a stator impact shell and a co-operating rotary impact shell, at least one of which is concave to form with the other a circular processing chamber or impact chamber that is preferably relatively narrow, being substantially smaller in axial dimension than in diametrical dimension. The material to be processed is introduced at a central zone of the chamber preferably through a central feed opening in the stator impact shell. The two shells are slightly spaced apart and are formed with co-operating rim portions Which form a circumferential slot for discharge of the processed material from the impact chamber.

Mounted in this processing chamber is an impact rotor or impeller and both the rotary impact shell and the impact rotor are actuated for rotary movement relative to each other, preferably in opposite directions. The two shells have conical inner wall portions of broken surface configurations converging on the circumferential discharge slot and the rotor has a corresponding peripheral configuration. In this manner the impact rotor cooperates with the converging walls to form a relatively thin peripheral processing zone of V-shaped crosssectional configuration with the discharge slot of the impact chamber at the apex of the V. The broken surface of conical converging Walls provides numerous impact surfaces in the peripheral processing zone and may be of various configurations for this purpose.

Preferably the impactgrotor also co-operates with the Patented June 12, 1956 impact chamber to provide a clearance space that extends radially in all directions from the feed opening of the chamber to the circumferential discharge slot. Preferably the impact rotor has suitable impact blades adjacent this clearance space and inlike manner the adjacent portions of the chamber walls may be formed with suitable vanes, ribs, bosses or the like, to provide the additional impact surfaces. In the preferred practices of the invention, this clearance space is progressively narrowed in cross-section to converge on the narrow peripheral processing zone so that the progressively reduced pieces of material will be progressively confined as they migrate centrifugally to the peripheral processing zone.

While the clearance space leading to the peripheral processing zone may be on either or both sides of the impact rotor, preferably the clearance space is primarily between the impact rotor and the stator impact shell. The impact rotor may have central radial web that initially confines the newly introduced material to this clearance space between the rotor and the stator shell. A feature of the preferred practice of the invention is the adjustability of the width of the circumferential discharge slot to control the particle size or fibre size of the finished product and a further feature is the concept of making at least one of the two shells adjustable axially relative to the other for the purpose of not only varying the width of the circumferential discharge slot, but also of varying both the thickness of the peripheral processing zone and the depth of the progressively constricted clearance space leading to the peripheral processing zone.

An outstanding feature of the invention, is its capability for reducing materials to fine particles or fibres with minimum heating eifect on the material. This capability makes possible continuous processing on a large scale of various materials that are susceptible to damage by heat such as materials which must be maintained frozen and materials having exceptional low melting points. The invention has been used successfully to grind to powder .form a thermo-plastic material that has a melting point of only 96 degrees F., and becomes more or less viscous at only degrees F.

Various features of the invention contribute to this capability for low temperature processing of materials. One important feature in this regard is that the structure in the region of the clearance space and in the region of the peripheral processing zone is so dimensioned and arranged, and the speeds of operation of the rotary shell and rotor are so adjusted that the pieces of material in process are in contact with the apparatus surfaces only a small fraction of the process time, the particles being in movement in the airstream across the process chamber for the major portion of the processing time.

Another contributing feature is the provision for a high rate of flow cooling air through the apparatus. For this purpose the rotor and the rotary shell are constructed to function as an effective centrifugal blower as well as to function as material-processing members. A further contributing feature is the construction of the device for high speed, high capacity operation to reduce the processing time and thereby reduce the opportunity for heat transfer from the apparatus to the material in process. A piece of material introduced into the process chamber may be discharged in powder form in a time interval as short as one-half second or shorter. In a preferred practice of the invention, a still further feature in this regard is the provision of a Water cooling system to minimize the temperature of the apparatus walls.

The preferred practices of the invention are further characterized by removable elements that may be replaced when worn excessively or may be interchanged with different elements when desirable for processing different materials. Thus fresh impact surfaces may be provided in the peripheral processing zone by replacing removable liners segments on the convergent conical walls of the peripheral processing zone. A feature in this regard is the concept of employing removable rings to retain the removable liner segments, the removable rings forming the rim portions of the two shells that define the circumferential discharge slot. These rings may be replaced to provide new slot walls when desired.

Other features and advantages of the present invention will be hereinafter apparent from the following description, particularly when taken in connection with the accompanying drawing, in which Figure l is a view, partly in side elevation and partly in section, of one embodiment of the invention;

Figure 2 is a front elevation of the same with the stator shell removed;

Figure 3 is a front elevation of a second embodiment of the invention;

Figure 4 is a front elevation of the second embodiment with the stator impact shell swung open for access to the interior of the processing chamber;

Figure 5 is a longitudinal section taken as indicated by the line 5--5 of Figure 3;

Figure 6 is a perspective view of the preferred form of rotor in the second embodiment of the invention;

Figure 7 is a fragmentary view of a rotor blade showing an auxiliary finger adjustably and replaceably mounted thereon;

Figure 8 is a section taken as indicated by the line 88 of Figure 7; and

Figure 9 is an enlarged perspective view of a replaceable segmental impact plate that may be employed in the peripheral processing zone of the impact chamber.

It is apparent that devices incorporating basic principles of the invention may be constructed in various ways. Two specific embodiments of the invention selected for disclosure herein will provide adequate guidance for those skilled in the art who may have occasion to apply the underlying principles of the invention to various specific purposes.

In the first embodiment of the invention shown in Figures 1 and 2, the principal parts of the device include: a base structure generally designated 10 which includes a base plate 11 and an upright arm 12; a circular housing shell 13 integral with the base structure; a stator impact shell 14 that completes the housing of the device; a rotary impact shell 15 that co-operates with the stator impact shell to form a circular impact chamber 16; and an impact rotor generally designated 20 mounted in the impact chamber to co-operate with the walls thereof. It is contemplated that the rotary shell 15 and the rotor 20 will be individually actuated for rotation relative to each other. In the preferred practices of the invention. the rotary shell and rotor will rotate in opposite directions at relatively high absolute speeds.

In the construction shown, the stator impact shell 14 is mounted on a hub 21 on the forward end of a hollow shaft 22, the shaft being journaled in a forward antifriction bearing 23, and in a second rearward bearing (not shown) that is mounted in the arm 12 of the base structure. A suitable drive pulley 25 on the shaft 26 of a motor 27 is connected by a suitable belt 28 with a driven pulley 30 on the hollow shaft 22 for the purpose of actuating the rotary impact shell 15.

The rotor 20 is shown mounted on an inner shaft 31, being retained thereon by a suitable nut 32. The inner shaft 31 is journaled inside the hollow shaft 22 by a suitable bearing 33 inside the hub 21 and by a second bearing (not shown) mounted inside the base structure arm 12. A drive pulley 35 on the shaft 36 of a second motor 37 is connected by a suitable belt 38 with a driven pulley 40 on the outer end of the shaft 31 for the purpose of actuating the rotor 20. As shown in Figure 2, the base structure 10 of the described rotary assembly and the two

motors

27 and 37 are preferably mounted on a relatively large and heavy support structure 41.

The housing shell 13 preferably has a series of centrally located ports 44 and the rotary shell 15 is provided with a similar series of ports 45 for the intake of air into the axial region of the impact chamber 16. The housing shell 13 includes a cylindrical wall 46 which is formed with a forward rim 47 of slightly reduced diameter to define a housing opening that is normally closed by the stator impact shell 14. For the purpose of admitting material to be processed in the impact chamber 16, the stator shell 14 has a central feed opening 50 and may be formed with a downwardly inclined feed duct 51 for deiivering material to the feed opening.

The stator impact shell 14 and the rotary impact shell 15 not only co-operate to form the impact chamber 16, but also are spaced apart at their rims to form a circumferential discharge slot 52 for the discharge of processed material. Preferably the discharge slot 52 is adjustable in width and a feature of the preferred practices of the invention is the concept of mounting the stator impact shell 14 on the housing shell 13 in an adjustable manner for this purpose. In the construction shown in the drawings, the cylindrical wall 46 of the stator shell 13 is formed with three equally spaced peripheral enlargements 53 in which are fixedly mounted corresponding screws 54. The stator impact shell 14 is provided with three corresponding radial arms 55 which are fixedly mounted on the stator impact shell by suitable studs 56 and nuts 57 and are suitably apertured to slidingly fit onto the three fixed screws 54. Each of the three radial arms 55 is confined between a pair of nuts 58 on the corresponding screw 54, which nuts may be adjusted to shift the stator impact shell bodily along its axis towards and away from the cooperating rotary impact shell 15.

At least one of the two

impact shells

14 and 15 is of concave configuration for the purpose of forming the impact chamber 16, both of the shells being concave in the present embodiment of the invention. In the construction shown, the two impact shells are formed with flat walls in their central regions and are formed with conical walls in their outer regions, which conical walls converge to the circumferential discharge slot 52. A feature of the preferred practices of the invention is the concept of lining these conical wall portions with replaceable impact plates which may be made of special wear-resisting alloys. Thus, as shown in Figure 2, a conical series of segmental impact plates 60 may line the conical wall portion 61 of the rotary impact shell 15 and, as indicated in Figure 1, a similar conical series of segmental impact plates 62 may line the conical wall portion 63 of the stator impact shell 14. The exposed faces of the plates are irregular or of broken configuration as they are formed with flutes, grooves, dovetail recesses or the like. In the construction shown, the segmental impact plates 60 are retained between a shoulder 64 of the rotary impact shell 15 and a co-operating retaining ring 65, the retaining ring being releasably secured by suitable screws 66. In like manner, the segmental impact plates 62 may be retained between a shoulder 69 of the stator impact shell 14 and a co-operating retaining ring 70 that is releasably secured by suitable screws 71.

Preferably the periphery of the impact rotor 20 is of a convergent configuration conforming to the crosssectional convergent configuration of the two series of segmental impact plates 60 and 62 on the conical wall portions, respectively, of the two impact shells, so that the periphery of the rotor 20 co-operates with the impact chamber 16 to form what may be termed a peripheral processing zone 72 that is of relatively smal dimension in axial depth and is of V-shaped configuration with the circumferential discharge slot 52 at the apex of the V. It is contemplated that the segmental impact plates 60 and 62 lining this peripheral processing zone will be of broken configuration to provide numerous impact surfaces around the periphery of the impact rotor 20. The surface configurations of the segmental impact plates 60 and 62 may for this purpose be characterized by such forms as grooves, depressions, ribs, lugs, bosses, points, sharp edges, and the like.

It is further contemplated that there wil be suitable clearance space between the impact rotor 20 and the walls of the impact chamber 16 with such clearance space extending radially from the region of the feed opening 50 to the peripheral processing zone 72 and with the clearance space decreasing as it approaches the peripheral processing zone. Preferably this clearance space is primarily on one side of the impact rotor 20. Thus, Figure 1 shows a clearance space 75 between the impact rotor 20 and the forward stator impact shell 14. While either or both the rotor 20 and the stator shell 14 may be of concave configuration for this purpose, the clearance space 16 in this instance is formed by making the rotor 20 of concave configuration 'with respect to the central wall of the stator impact shell 14. Thus the impact rotor 20, shown in Figure 1, progressively increases in thickness from its axial region to its peripheral region.

The impact rotor-20 may be -of various constructions. In the particular form shown in Figures 1 and 2, the rotor comprises a plurality of blades 78 that extend outward to the peripheral processing zone 72. Preferably the series of blades 78 is integral with and interconnected by a central web or disc 80 integral therewith. It will be noted that-the web 80 lies closely adjacent to the central flat portion of the rotary impact shell 15 so that material entering the feed opening 50 of the impact chamber will be directed against the web 80 rather than against the flat wall portion of the rotaryirnpact shell 15.

Preferably the circumferential discharge slot 52 is surrounded by a suitable annular discharge chamber 82 which is formed by the housing shell 13 with its cylindrical wall 46 in co-operation with adjacent portions of the stator impact shell 14 and the rotary impact shell 15. The finely divided processed material received by the annular discharge chamber 82 is released through a lower discharge opening 83. The discharge opening 33 is the entrance to a discharge passage 84 that extends downward- 1y through the base structure and the supporting struc ture 41.

The operation of the device may be readily understood from the foregoing description. The material to be comminuted or disintegrated is fed through the feed duct 51 and the feed opening 50 into the impact chamber 16 at a rate to occupy only a small portion of the available space in the impact chamber so that the pieces of material in process may have ample freedom to move at high velocity through the air from one impact surface to another. The principal impact surfaces are provided by the rotor blades 78 and the two conical series of segmental impact liners 60 and 62 in the peripheral processing zone 72, but other impact surfaces are provided by the central wall of the stator impact shell 14around the feed opening 50 and by the forward face of the rotor web 80.

Each piece of the material in process is repeatedly struck and accelerated by the impact surfaces of the rotary impact shell and the rotor 20 and repeatedly strikes against the stationary impact surfaces of the stator impact shell 14. Thus with the rotary impact shell 15 and the rotor 20 operating in opposite directions athigh relatively angular velocity, the pieces of material in process are repeatedly accelerated and repeatedly deflected, the pieces ricocheting from stationary impact surfaces back into the paths of rotating impact surfaces.

The impact surface configurations may be specialized for particular materials to be processed in the device, especially the configurations of the surfaces of the segmental impact plates, but with almost any broken configuration .providingnumerous individual impact surfaces,

suitable operating speeds may be found for the rotary impact shell 15 and the rotor 20 that will result in efiicierrt disintegration of any particular substance. The specific effect of the impacts on the material in process will depend largely on the character of the material. The effect may be to tear, to abrade, to shred, to peel, to split, to shatter, etc.

Because the speeds of rotation are usually relatively high, the major portion of the impacts tend to occur in the outer regions of the impact chamber. When the pieces in process are reduced in thickness to a sufficient degree, they pass into the peripheral processing zone 72 between the rotor and the segmental impact plates for high velocity movement on exceedingly short paths with high frequency impacts between the periphery of the rotor and the segmental impact plates. This final acceleration of the disintegration process reduces the material to particles of sufficient fineness to be thrown out centrifugally through the circumferential discharge slot 52 into the surrounding annular discharge chamber 82 to drop into the discharge passage 84.

Among the factors that account for the relatively low heating effect of the process on the material are, first, the fact that a piece of material is processed rapidly and lingers only briefly in the impact chamber 16, second, the fact that the material is in actual contact with the structure of the device for only a small portion of the processing period, third, the fact that the material in process is repeatedly projected into a highly effective stream of cooling air, and fourth, the fact that the relatively moving impact surfaces create small high velocity air vortices that have substantial cooling effect and tend to entrain any particles on the metal surfaces. The device functions as an effective centrifugal blower as well as a mechanically abrading device, air entering the axial region of the impact chamber 16 through the feed opening 50 and through the

intake ports

44 and 45, the air being discharged centrifugally through the circumferential discharge slot 52 into the annular discharge chamber 82 to pass out through the discharge passage 84. Thus the air functions not only to cool the material in process, but also to entrain the material in process to carry the material through the peripheral processing zone 72 into and through the centrifugal discharge slot 52. In addition, the air stream performs the useful function of continually cleaning the various impact surfaces.

One important feature of the device of the present invention is the absence of metallic elements which perform a grinding or crushing operation as in conventional ball and hammer mills. This eliminates the temperature rise inherent in conventional disintegrating equipment and also obviates the possibility of sparking produced by metal striking metal. rise possible with the device of the present invention, and the fact that the pulverizing can be carried out without a grinding operation likely to produce sparking, renders the device particularly adapted for grinding explosive materials which have been very dangerous to process heretofore.

It can be emphasized again that the extremely low temperature rise also makes possible the distintegration or pulverization of organic material that must be maintained at a relatively low temperature to prevent deterioration of certain properties of the material being processed. For example, in the extraction of certain pharmaceutical compounds from organs of animals, the organs must be pulverized at temperatures on the order of 60 degrees below zero, centigrade. Thus, pancreas of calves frozen to 60 degrees below zero, centigrade, have been pulverized in the device of the present invention at a temperature increase of only one degree centigrade.

The second form of the invention shown in Figures 3 to 9, inclusive, is of the same general character as the first form and has the same principal parts. As best The extremely low temperature shown in Figure 5, the device includes a base structure, generally designated 90, that is formed with an upwardly extending arm 91 and is integral with a housing shell, generally designated 92. The housing shell 92 is formed with a circular peripheral wall 93 and preferably is of hollow construction to contain a body of water 94 which is part of a suitable circulating cooling system.

The housing of the device includes not only the housing shell 92, but also a stator impact shell, generally designated 95, and a large ring member 96 that surrounds the stator impact shell and abuts the circular peripheral wall 93 of the housing shell 92. In the construction shown a hollow O-ring 97 seals the juncture between the ring member 96 and the stator impact shell 95 and a second hollow O-ring 98 seals the juncture between the ring member and the circular peripheral wall 93.

Preferably the stator impact shell 95 is adapted for removal in a convenient and rapid manner for access to the interior of the device, when required, and preferably the stator impact shell is also adjustable axially relative to the housing shell 92 in the same general manner and for the same general purpose as heretofore described. For this purpose, the stator impact shell 95 may be adjustably mounted on the ring member 96 for axial adjustment relative thereto and the ring member may be hingedly mounted on the housing shell 92.

In the particular construction shown in the drawings, the ring member 96 carries three forwardly projecting fixed screws 100 at three equally spaced circumferential points and the stator impact shell 95 has three corresponding angular ears 103 (Figures 3 and each of which has an aperture 104 to slidingly embrace the corresponding screw. Each of the angular ears 103 is confined between two manually

adjustable nuts

105 and 106 on the corresponding screw 100 so that the stator impact shell may be adjusted axially as desired.

As best shown in Figures 3 and 4, the ring member 96 has an integral hinge wing 107 and the housing shell 92 has a co-operating hinge wing 103, which two hinge wings are pivotally interconnected by a suitable hinge pin 110 to permit the ring member, together with the stator impact shell 95, to swing from the normally closed position shown in Figure 3 to the open position shown in Figure 4. For the purpose of holding the ring member 96 closed in a quickly releasable manner, a suitable pair of eye bolts 111 may be provided, each eye bolt carrying a clamping nut in the form of a hand wheel 112. Each of the eye bolts 111 is pivotally mounted on a pin 113 between a pair of cars 114 on the housing shell 92 to swing between the released position shown in Figure 4 and the clamping position shown in Figure 3. In its clamping position, each of the eye bolts 111 extends through a slot 115 in a corresponding car 116 that is integral with the ring member 96, the manually rotatable clamping nut 112 being tightened against the outer face of the ear.

Preferably the stator impact shell 95, like the housing shell 92, is water cooled and for this purpose is of hollow construction to contain a body of water 117. The water is maintained in circulation as part of the cooling systemby means of two flexible hoses 118.

The stator impact shell 95 co-operates with a rotary impact shell, generally designated 140, to form the usual circular impact chamber 145 and also forms with the rotary impact shell the usual circumferential discharge slot 146. For the introduction of material into the impact chamber 145, the stator impact shell 95 has a central feed opening 147 and is equipped with a feed duct or spout 148 that is attached by screws 149.

The rotary impact shell 140 is mounted by screws 150 on a hub 151 that is integral with a hollow shaft 152. A

forward bearing 155, enclosed by bearing housing 156 and cover plate 157, journals the forward end of the l hollow shaft 152. The rear end of the shaft is journaled in a second bearing 158 that is enclosed by a bearing housing 159 and covered by a plate 160. The forward bearing may be protected by a pair of sealing

rings

161 and 162, together with a felt ring 163 secured by a retaining ring 164, and the second bearing 158 may be protected by sealing rings 165 and 166 at opposite ends of the bearing housing 159. For actuation of the rotary impact shell 140, a grooved pulley 170 keyed to the hollow shaft 152 is connected by multiple V-belts 171 with a similar pulley 172 driven by a motor 173.

An impact rotor, generally designated 175, for the impact chamber 145 is mounted on the end of inner shaft 176 and is secured thereto by a nut 177 and a safety screw 178. The inner shaft 176, which extends through and beyond the hollow shaft 152, is journaled at its forward end by a bearing 179 in the hub 151 behind a cover plate 180 and a sealing assembly 181.

This sealing assembly comprises a reinforced plastic ring 181a and a sealing plate 18112 held in position by a pair of bushings, the sealing plate being mounted intermediate the bushings as clearly shown in Figure 5.

The sealing assembly very effectively prevents entrance of pulverized material, which might enter behind the rotor, from working into the bearing assemblies supporting the shafts. This is particularly important where the material being processed would form an explosive mixture with oil and greases present in the shaft-supporting bearings. There is little likelihood, however, of material entering between the rotor and impact seal. This is so, for once the material enters the device through the feed opening it is immediately impelled away from the rotor and escapes from the device through the discharge slot 146.

The rear end of the inner shaft 176 is also journaled in a bearing 182 in the bearing housing 159 behind a cover plate 183. A second grooved pulley 187 on the rear end of the inner shaft 176 is connected by multiple V-belts 188 with a pulley 189 driven by a second motor 190 for the purpose of actuating the impact rotor 175.

The rotary impact shell 140 and the impact rotor 175 are driven by the corresponding

motors

173 and 190 in a manner to provide a high magnitude of relative speed between the two and this purpose may be accomplished by driving the rotary impact shell and impact rotor in the same direction at different speeds. Preferably, however, the rotary impact shell and the impact rotor are driven in opposite directions, the two speeds of rotation depending upon such factors as the diameters of the rotating parts, the character of the material being processed and the degree of fineness desired in the finished product. Usually highly satisfactory results may be obtained by driving the impact rotor 175 at a substantially higher speed than the rotary impact shell 140.

In a device of the character described having an impact chamber 145 of approximately 30 inch diameter, for example, the impact rotor may be driven at 3500 R. P. M. and the rotary impact shell may be driven at 1600 R. P. M. or again the impact rotor speed may be 4100 R. P. M. and the impact shell speed may be 3700 R. P. M. It the impact chamber is smaller, say on the order of 18 inches in diameter, the impact rotor may be driven at 1200 R. P. M. and the rotary impact shell may be driven at 400 R. P. M. These speeds may be increased when desired. Relatively high speeds are desirable when the material in process has a low melting point and must be protected against undue rise in temperature by passing rapidly through the process. Usually it is helpful also to feed the material at a relatively low rate when low temperatures are to be maintained. In other words, the relative speeds of the rotor and impact shell, and the rate of feed of the material into the processing chamber will depend to a great extent on the material being processed.

described embodiment of the invention, being formed with two inner

conical Walls

191 and 192 that converge towards the circumferential discharge slot 146. These two conical wall portions are lined, respectively, by a conical series of segmental impact plates 193 and a second conical series of segmental impact plates 194. As heretofore stated, such segmental bafile plates have surfaces of broken configurations and may be of various forms for this purpose.

In the present embodiment of the invention, the preferred configuration for an impact plate is shown in Figure 9 in which a segmental impact plate 193 is formed with sharp-edged ribs 195 separated by grooves 196 of the same width. It will be noted in Figure 9 that the segmental impact plate 193 has beveled

edges

197 and 198, the purpose of which is to permit anchorage of the plates by suitable retaining rings.

As best shown in Figure 5, the segmental impact plates 193 of the stator impact shell 95 are held by a retaining ring 200 that is anchored by suitable screws 201 in cooperation with a second retaining ring 204 that is releasably held by screws 205. In like manner the segmental impact plates 194 of the rotary impact shell 140 are held in place by a retaining ring 207 releasably secured by screws 208 and by a second co-operating retaining ring 209 that is releasably anchored by screws 210. A feature of this construction is that the two retaining

rings

204 and 209 have a dual function since the two rings also serve as replaceable rim members for the two impact shells and may be replaced whenever it is desirable to renew the surfaces of the circumferential discharge slot 146.

The impact rotor 175 may be of the same general configuration as the impact rotor in the first described embodiment of the invention. Thus, as best shown in Figures and 6, the impact rotor may comprise a plurality of radial blades 214 and a central web or disc 215 integral therewith. Preferably two of the blades 214a, positioned diametrically opposite each other, have root portions 216 of greater width than the corresponding portions of the other blades, these root portions 216 protruding forward towards the stator impact shell 195. As may be seen in Figure 5, the periphery of the impact rotor 175, that is to say, the end portions of the various blades 214, are of convergent configuration to form with the two series of

segmental impact plates

193 and 194, a thin V-shaped peripheral processing zone 217, with the circumferential discharge slot 146 at the apex of the V.

The circumferential discharge slot 146 is surrounded by an annular discharge chamber 220 which communicates with a bottom discharge passage 221. The discharge passage 146 may be connected with one or more discharge ducts if desired. For example, as best shown in Figures 3 and 4, a suitable hopper 222 may receive material from the discharge passage 221 for delivery to a pair of discharge ducts 223.

A feature of this second embodiment of the invention is the concept of mounting driven vanes in the discharge chamber 220 both for the purpose of continually sweeping material therefrom for centrifugal discharge into the passage 221, and for the purpose of serving as additional blower means for pumping air through the apparatus. A further feature of the second embodiment of the invention is the concept of mounting such vanes on the rotary imp act shell 140to be driven thereby.

As best shown in Figures 3 and 4, the rotary impact shell 140 is formed with a circumferential radial flange 227, which serves as one side wall of the annular discharge passage 220, the other side wall being the ring member 96. Suitable angle members 228 are mounted on the flange 227 by bolts .229 to serve as the desired vanes. In this instance, there are two diametrically positioned angle members 228, but more maybe added, the blower effect increasing With the number of the vanes.

A hlrther feature of this second embodiment of the invention is the provision of further relatively large impact surfaces by the stator impact shell for-initial processing of material introduced through the feed opening 147. For example, as shown in Figures 4 and 5, the stator impact shell 95 may be formed with relatively heavy radial lugs 230 opposite the mid-portions of the rotor blades 214. It can be seen in Figure 5 that the radial lugs 230 co-operate with the blades 214 to form a clearance space that extends from the feed opening 147 to the peripheral processing zone 217 and that this clearance space is progressively restricted.

This second embodiment of the invention operates in substantially the same manner as the first embodiment of the invention and being water cooled is especially adapted for processing materials that must be kept at relatively low temperatures. The degree of fineness to which the material is broken down is governed primarily by the width of the circumferential discharge slot 146 and the thickness of the peripheral processing zone 217. It is to be noted that when the nuts and 106 are manipulated to change the width of the circumferential discharge slot 146, the spacing between the rotor blades 214 and the forward segmental impact plates 193 is likewise changed, and in addition the dimension of the radial clearance space leading to the peripheral processing zone is changed. Thus, if the adjustment of the

nuts

105 and 106 increases the width of the circumferential discharge slot 146, the dimensions of one-half of the peripheral processing zone 217 will also be increased along with the width of the clearance space, so that larger pieces of the material in process will be permitted to enter the peripheral processing zone and to pass through the peripheral processing zone to the circumferential discharge slot 146.

It has been found that the effectiveness of the described apparatus for processing gummy substances may be greatly increased by adding a suitable finger to the impact rotor 175, for example, as indicated in Figures 7 and 8. For this purpose, one of the rotor blades 214 is shown formed with an enlargement 232 on one of its faces adjacent the tip of the blade, this enlargement having teeth for adjustable engagementwith corresponding teeth on a finger member 233. A suitable screw 234 releasably holds the finger member 233 on the rotor blade with the teeth of the finger member engaging the teeth of the enlargement 232. Thus the interengaged teeth not only hold the finger member rigid on the blade, but also permit radial adjustment of the finger member. The finger member has a pointed outer end which extends into the peripheral processing zone 217 and may even extend partially into the circumferential discharge slot 146, so that the finger will continually sweep away any gummy or sticky substance that may tend to clog the circumferential discharge slot and the peripheral processing zone adjacent the slot.

Here again, the material being processed is maintained in an atmosphere wherein there are no impacting elements which might produce a spark which would serve to ignite explosive materials. Thus, the embodiment now being described can also be used for grinding or pulverizing explosive materials which have been heretofore very difficult and dangerous to process.

Also, it should again be seen, that the material processed is only briefly in contact with the impact elements of the chamber. As the material is entrained and carried through the chamber by the high velocity, high turbulent air moving through the chamber, there is little likelihood of the material being heated as it is processed. Thus, again the embodiment just described is particularly adapted to process materials which are susceptible to damage by even relatively low temperature rises.

The method of the present invention, whether carried out with either embodiment of the device herein disclosed andclaimed, or with devices difiering therefrom, comprises, as should now be understood, the steps of introducing the material to be processed into a zone defined 'in part by a rapidly rotating wall element; and subjecting the material, while confined within the zone, to high velocity impact blows as said particles are moved by centrifugal forces set in motion by the rotating wall element outwardly of the zone. The discharge movement of the material is augmented in the method disclosed by a high velocity, highly turbulent air stream moving through said chamber and exiting at a discharge opening to carry the material therethrough as the particles thereof are reduced to a size sufficiently small to pass through said discharge opening. The method includes the highly important step of subjecting the material introduced into the zone or chamber to rapidly successive, high velocity impact blows to cause the same to strike repeatedly against each other and against the impact surfaces formed internally of the zone or chamber as the particles are entrained and carried by the air stream through the zone or chamber. It will be seen that in carrying out the method, the material is actually driven at a high velocity against the impact surfaces of the rotor and shells and ricochets from one surface to the other in the disintegration process as it is moved toward the discharge opening formed by the circumferential slot.

Although the now preferred embodiments of the present invention have been shown and described herein, it is to be understood that the invention is not to be limited thereto, for it is susceptible to changes in form and detail within the scope of the appended claims.

I claim:

1. A device of the character described for dividing material into fine particles, comprising in combination: a pair of impact shells of concave facing configuration positioned face-to-face and coaxially mounted and forming an impact chamber of circular configuration, one of said shells having a central opening therein for feeding material into said chamber, said two shells having aligned rim portions forming converging wall means defining a circumferential discharge slot, said impact chamber having inner walls of broken configuration to provide numerous impact surfaces including impact surfaces near said slot; an impact rotor in said chamber comprising a plurality of radially extending blades having impact surfaces positioned adjacent said chamber impact surfaces to cause pieces of material to strike back and forth repeatedly between the rotor impact surfaces and the chamber impact surfaces; the blades of said impact rotor having tip portions providing clearance relative to said chamber restricted in the region of discharge slot to break the material into fine particles in said region; and power means to rotate at least one of said impact shells and said impact rotor for high speed relative rotation therebetween.

2. A device as set forth in claim 1 in which said power means operates the driven impact shell and the impact rotor in opposite directions.

3. A device as set forth in claim 1 in which said rotor is of open construction with the side edges of said blades exposed to one of said impact shells to permit pieces of material in process to strike back and forth between the blades and said one shell.

4. A device as set forth in claim 3 in which the clearance between said blades and said one impact shell is substantially greater than said restricted clearance in the region of said discharge slot.

5. A device as set forth in claim 4 in which said side edges of the blades are adjacent the non-rotating impact shell and the clearance between said rotor and said nonrotating impact shell progressively narrows towards the outer edges of said blades.

6. A device as set forth in claim 5 in which said rotor has a central radial web cutting off said blades from the central portion of the driven impact shell.

7. A device of the character described for dividing .material into fine particles, comprising in combination: two impact shells axially aligned and forming an impact chamber of circular configuration, one of said shells having a central opening therein for feeding material into said chamber; means mounting the other of said shells for rotation said two shells having rim portions forming a circumferential discharge slot, one of said impact shells having an inner peripheral wall of broken configuration adjacent said slot to provide numerous impact surfaces; a rotor having a plurality of flat radially extending blades having impact surfaces with peripheral edges adjacent said peripheral wall; means mounting said rotor for rotation about an axis coincident with the axis of rotation of said other shell; and means to rotate said other shell and said rotor for relative movement between the two thereby to cause pieces of material in the chamber to strike back and forth repeatedly between said plurality of impact surfaces of the rotor and said impact surfaces of said peripheral wall.

8. A device as set forth in claim 1 in which the stator impact shell is formed with the opening and is pivotally mounted to swing open for access to said chamber.

9. A device as set forth in claim 1 in which said impact rotor has at least one finger adjustably carried by a blade thereof and projecting into said peripheral processing zone to clear away deposits of material along said discharge slot.

10. A device as set forth in claim 9 in which the end of said finger is of convergent configuration to conform with the configuration of said peripheral processing zone adjacent the slot.

11. A device of the character described for dividing material into fine particles, comprising in combination:

a stator impact shell and a co-operating rotary impact shell, at least one of which is concave to form with the other an impact chamber that is of circular configuration in one plane and of elongated configuration in a second plane through the axis of the chamber, said stator shell having a central opening for feeding material to the chamber, said two shells having rim portions spaced apart to form a circumferential slot for discharge of the fine particles from the chamber, said two shells having conical inner wall portions of broken surface configuration converging on said slot; an impact rotor in said chamber formed with a plurality of spaced blades extending outward toward said slot, the outer extremities of said blades being of convergent configuration to form with said converging inner wall portions a thin peripheral processing zone of V-shaped cross-sectional configuration, with said discharge slot at the apex of the V; and means to rotate both said rotary impact shell and said impact rotor relative to each other to cause the material introduced through said feed opening to be reduced in size by repeated projections across the clearance space between the rotor and the chamber Walls and across said peripheral processing zone with high velocity impacts by said rotor and said shells and to cause the progressively diminishing particles of the material to migrate centrifugally through said peripheral processing zone to said discharge slot.

12. A device as set forth in claim 11 in which said discharge slot is narrower than the cross-sectional dimension of said peripheral processing zone whereby the dimension of the slot determines the size of the processed particles.

13. A device as set forth in claim 11 in which said impact rotor, as intersected by said second plane, increases progressively in cross-sectional dimension from the axis of the impact rotor to said peripheral processing zone to 14. A device as set forth in claim 11 in which the conical inner wall portions of said shells are lined with removable impact plates of broken surface configuration. 15. A device as set forth in claim 14 in which said impact plates are removably secured by removable rings and said rings form the walls of said discharge slot.

16. A device as set forth in claim 11 in which said impact rotor has blades extending outward to said peripheral processing zone and has a radial web between said feed opening and said rotary impact shell.

17. A device as set forth in claim 16 in which a relatively small number of said blades have portions extending beyond the rest of the blades towards said stator impact shell.

18. A method of disintegrating material comprising the steps of: introducing the material particles into a processing zone defined in part by a rapidly rotating wall element; reducing the size of said material particles by subjecting the material particles, while confining the same in said zone, to high velocity impact blows as said particles are moved by centrifugal forces generated by said rotating Wall element outwardly of said zone; and discharging said particles from said zone through an exit circumscribing said zone as the impact blows reduce said particles to a size sufficient to pass through said exit.

19. A method of disintegrating material comprising the steps of: introducing the material particles into a processing zone defined in part by a rapidly rotating wall element; reducing the size of said material particles by subjecting the material particles, While confining the same in said zone, to high velocity, high frequency impact blows as said particles are carried by a high velocity, highly turbulent air stream and moved by centrifugal forces generated by said rotating wall element outwardly of said zone; and discharging said particles carried by said airstream from said zone through an exit circumscribing said zone as the impact blows reduce said particles by said impacts to a size sufiicient to pass through said exit.

20. A method of disintegrating material comprising the steps of: introducing said particles centrally into a processing chamber of circular configuration formed by impact shells coaxially mounted with the rims thereof defining a circumferential discharge slot; rotatably driving one of said shells in a direction opposite to the direction of rotation of an impact rotor within said chamber to thereby subject said particles to rapidly successive high velocity impacts against each other, said rotor, and adjacent surfaces of said shells as said particles are carried by centrifugal forces toward said circumferential discharge slot; and directing a high velocity air stream through said chamber for discharge through said slot to carry said material particles therethrough as said particles are reduced by said impacts to a size sufficiently small to pass through said slot.

21. A method of disintegrating material comprising the steps of: introducing the material particles centrally into a processing chamber of circular configuration defined by a stationary wall element and a cooperating rotary wall element spaced therefrom to provide a circumferentially arranged discharge slot; subjecting the material particles introduced into said chamber to rapidly successive, high velocity impact blows to cause the same to strike against each other and against impact surfaces formed internally of said chamber as said particles are carried by centrifugal forces generated by said rotary wall element outwardly of said zone; and directing a high velocity air stream through said chamber for discharge through said slot to carry said material particles therethrough as said particles are reduced by said impacts to a size sufficiently small to pass through said slot.

22. A method of disintegrating material comprising the steps of: introducing said particles centrally into a processing chamber of circular configuration having abrading surfaces internally thereof formed by adjacent surfaces of impact shells coaxially mounted with the rims thereof defining a circumferential discharge slot; rotatably driving one of said shells in a direction opposite to the direction of rotation of an impact rotor within said chamber to thereby subject said particles to rapidly successive, high velocity impact blows whereby said particles are driven at relatively high rates of velocity against each other, said rotor, and the abrading surfaces of said shells as said particles are carried by centrifugal forces toward said circumferential discharge slot; and directing a high velocity air stream through said chamber for discharge through said slot to carry said material particles therethrough as said particles are reduced by said impacts to a size sufliciently small to pass through said slot.

References Cited in the file of this patent UNITED STATES PATENTS 247,749 Dawson Oct. 4, 1881 976,535 Woodcock Nov. 22, 1910 1,046,678 Theesing Dec. 10, 1912 1,591,283 Charto-n et al. July 6, 1926 1,723,443 Roth Aug. 6, 1929 2,164,409 Johnson July 4, 1939 FOREIGN PATENTS 17,424 France June 13, 1913 (Addition to No. 406,503) 464,282 France 1 Jan. 9, 1914 698,991 Germany Nov. 20, 1940 924,886 France Mar. 17, 1947