US2757872A

US2757872A - Crushing mill

Info

Publication number: US2757872A
Application number: US331131A
Authority: US
Inventors: Rehwald Gerhard; Mehlbeer Heinrich
Original assignee: Stolberger Zink AG
Current assignee: Stolberger Zink AG
Priority date: 1952-01-15
Filing date: 1953-01-14
Publication date: 1956-08-07
Anticipated expiration: 1973-08-07

Description

Aug.7,1956 G. RHWALD mL i 2,757,872

' CRUSHING MILL Filed Jan. 14, 1953 v2 Sheets-Sheet l l 25 r/ Il* i A VIII' INVENToRs GERHARD REHWALD 2| BY HEINRICH MEHLBEER /M uw ATTORNEY Aug. 7, 1956 Filed Jan. 14, 1953 G. REHWALD ET AL CRUSHING MILL 2 Sheets-Sheet 2 INVENToRs GERHARD REHWALD BY H lNRlCH MEHLBEER -l Q. uw

ATTORNEY United States Patent O "ice CRUSHING MILL Gerhard Rehwald, Aachen, and Heinrich Mehlbeer, Gey Uber Duren, Germany, assignors to Stolherger Zink Aktiengesellschaft fr Bergbau und Huttenbetrieb, Aachen, Germany, a firm Application January 14, 1953, Serial No. 331,131

Claims priority, application Germany January 15, 1952 11 Claims. (Cl. 241-275) This invention relates to a crushing mill, particularly of the centrifugal type in which crushing pins are mounted in a carrier plate or head adapted to rotate on a vertical shaft. Mills of this kind are often employed for the disintegration of soft and medium-hard materials in piece form and on account of their particular mode of operation, are particularly well suited for the selective crushing of such materials.

It was not possible, hitherto, to use these centrifugal pin type crushing mills for finely disintegrating hard materials, or for selectively crushing mixtures or conglomerates containing highly abrasive ingredients which may be harder than the material of which parts of the mill effecting the crushing are made. The reason for this limitation may be found in the fact, that heretofore no crushing mill of the aforesaid centrifugal type has been known which, under full utilization of its capacity, would satisfy the following demands:

(a) Limitation of wear to the working parts of the mill.

(b) Simple exchange of all parts which are subject to wear, particularly of the parts effecting disintegration.

(c) Complete utilization of the wearing parts.

(d) Adaption of the crushing forces to the degree of disintegration of the product.

(e) Easy repair of the entire working assembly.

() Minimum of dust.

(g) Disintegration by beating and impact without squeezing.

In view of the conventional centrifugal mills failing in most of these respects, the invention has for its main object the provision of a centrifugal pin type crushing mill in which most of the aforesaid demands will be complied with and which, therefore, will not be subjected to the disadvantages of the hitherto known machines of this kind. In fact, a mill in accordance with this invention is distinctly different from the known millsof this character as to represent an entirely new type for which the term impact mill seems appropriate. t

Another object of the invention resides in the provision of a mill in which means are provided for the propulsion of the material byl centrifugal force against shock-producing as well as internal and external impact means, said means being preferably concentrically arranged in a manner which greatly facilitates the selective action of the crushing mill.

A. further object of the invention resides in the formation of the actual working parts of the crushing mill of mutually independent parts easy of disassembly and ex- A change.

` impact which have been found to convey the best disintegrating effects to `the material.

2,757,872 Patented Aug. 7, 1956 With these and other objects in view the invention broadly resides in the provision of a pin type crushing or disintegrating mill in which a distributing disc or plate is provided to be supplied from above with the material to be treated, and in which concentrically within the ring of crushing pins, and outside thereof, impact surfaces are arranged in a certain mutual relation. The arrangement, in accordance with additional features of the invention, is preferably such that either the distributing plate forms a separately driven element independent of the rotary carrier supporting the crushing pins, or the distributing plate may be constructed to form part of the said crushing pin carrier itself.

Other objects and improvements of the invention may be gathered from the following description of the accompanying drawing, in which several embodiments of the new crushing mill are diagrammatically illustrated by way of example.

In the drawings:

Fig. l is an elevational sectional view of a crushing mill according to the invention.

Fig. 2 is a similar sectional View showing a modification of the mill.

Fig. 3 is a fragmentary view showing a modification of the mounting of the crushing pins in the mill of Fig. 1.

Fig. 4 is a fragmetary isometric view partly in section showing a modication of the feed hopper of Fig. l, and

Fig. 5 is a sectional elevational view of still another modification of the crushing mill.

In the embodiment of the invention as shown in Figs. l and 2 a centrifugal plate or distributing disc 1 and a rotary carrier 2 are shown as separate, independent parts disposed in a housing 18 including a disintegrating chamber. The centrifugal plate 1 is fastened to the top end of a rotary vertical shaft 3 and secured thereto by a closing cap 4 which is xed to the shaft by means of a bolt 5. The drill hole 6 in the cap above the head of the bolt 5 may be filled by means of pitch, resin, or other suitable material.

The upper surface of the centrifugal plate 1 is covered by a layer of wear resisting material attached thereupon in any suitable manner. This layer may be a flat layer 7 as is shown in Fig. 1 or a dished layer '7' as is shown in Fig. 2. The dished formation has the advantage of compensating due to its thickened circumference the increased wear experienced by the outer portions of the plate and to impart to the material to be disintegrated a slightly upwardly inclined centrifugal force while being thrown outwardly. `The carrier 2 is provided around its outer circumference with a plurality of pockets or bores for the reception of crushing pins 8. The pins 8 need not be fixed in the bores but may be loosely inserted as is indicated at 3i) as they are held in position by the centrifugal force acting upon them. It is preferable to provide on the upper surface of the carrier 2 a ring 9 of wear resisting material similar to the layer 7 or 7', which may consist of one or more parts and through which the crushing pins 8 protrude into the space above. The bores through ring 9 for pins 8 preferably provide a closer lit for the pins than the bores in the carrier 2. In this way the wearing ring 9 remains clamped in position without the necessity of being separately fastened to the carrier. lf desired, the pockets or bores for the reception of the pins 8 may be made of different depth, which will make it possible, to remove partly worn pins from the deeper pockets and to insert them into the pockets of lesser depth to replacethe more strongly worn pins at these places. Fig. 3 shows bores 30 and 31 respectively of different depth. This figure also shows that the axes of the bores may be slanted. It is also advisable to provide the pockets or bores for the pins 8 with bottom openings 10 through which a chaser or the like may be driven for forcing seized pins out of their pockets. If desired the bottom openings may be screw threaded so that by driving a screw bolt ltherethrough, as is shown in Fig. 2, the pins may be forced out of their holes in carrier 2 and ring 9. Another way of removing worn pins is by the provision of slots 12 crossing the said pockets or bores. Byl driving wedges into these slots below the pins 8 the pins will be freed and may then be pulled out more easily.

In the embodiment shown in Figs. l and 2 the carrier 2 is designed to form the bearing for the shaft 3 of the centrifugal plate 1, whereby the shaft 3 may be driven over a pulley 14, and the carrier 2 over a pulley 15 in the same or opposite rotational direction and at the same or varying speeds. The carrier 2 is journaled in a sleeve or bushing 16 which is supported on ribs 17 in housing l of the machine. A lateral opening 1.9 in the said housing serves for the passage of the driving belts for both, the Shaft 3 and the carrier 2. rThe belts (not shown) and pulley 14, are encased in a chamber 29 within the hopper-like lower part 21 of the housing and thus protected against damage by tre disintegrated material passing through hopper 21. Between the bushing 16 and the lower surface of the carrier 2 a labyrinth packing 22 or other tightening means may be provided.

At its top the housing 13 has a wide opening which is closed by a lid 23. An opening in the lid serves for the passage of a feed means in form of a chute or coaxial with the shaft 2. The hopper may also be arranged at a slant so that at the moment of introduction of the material, suitably in the rotary sense of the centrifugal plate or disc 1, the material will already have a certain velocity. Such initial velocity tends to reduce the wear on the upper surface of the plate. Fig. 4 shows a hopper 24 which feeds the material spirally and eccentrically upon distributing disc or plate 1. A sleeve or ring 25 is provided to depend from the lid 23 into the disintegrating chamber of the mill. The outer surface of the sleeve serves as the inner impact surface 26 for the disintegration of the material. For the purpose of adjusting the action of the impact sleeve or ring 25, the ring may be adjustable in relation to thc plate 1, but the distance of the lower edge of the ring from the face of the plate 1 should be not smaller than the largest pieces of theproduct. As indicated in Fig. 1, the ring 2S may be slightly inclined inwardly, which will facilitate the entrance of the pieces as they are precipitated by the action of the pins 8.

Outside the circle of crushing pins 2 an outer impact sleeve or ring 27 is provided. This ring is clamped in position by the lid 23 and also depends into the disintegrating chamber of the mill. The inner side 2S of the ring serves as the outer impact surface for the disintegration of the material propelled by the pins 8 against the said surface.

The part of the housing 18 which constitutes the disintegrating chamber and which is positioned in the zone of the impact action, is of annular cross section and of such diameter, that the outer impact ring 27 depends freely into the said disintegration space, whereby a cyclone action of the device is obtained.

The crushing mill in accordance with this intention operates as follows:

The pieces of material to be treated are introduced into the mill through the hopper 24 which will feed it onto the rotating distributing disc or plate 1. The centrifugal force propels the material outwardly in free flight against the crushing pins 8, whereby some pieces of the material becomes disintegrated by impact action.

Other pieces of the material are bandied by the pins 2 against the inner impact surfaces 26, from which they fall back onto the plate 1 in order again to be thrown outwardly.

carrier 2 into the lower part of housing 18 and thence out of 'the machine by the bottom opening thereof.

In the illustrated embodiments of the invention wear occurs particularly at the following parts or places:

1) On the upper surface of the distribution plate 1 by the friction or abrasion caused by the material,

(2) On the inner and outer impact surfaces due to impact,

(3) On the crushing pins E owing to impact and shock.

A moderate wear also occurs on the pin carrier 2 and also on thc upper surface of the ring 9 due to the collection of material in front of the crushing pins. The wear at these areas is relatively small for the reason of the upper external edge of the plate 1 or its protective layer 7 being sutiiciently high above the surface of the carrier 2, so that the material impinges upon the crushing pins only at a certain distance above the ring 9. A further reduction in the wear on the mentioned parts is effected by employing the dished configuration of the layer 7 as shown in Fig. 2. As a result, the direction of propulsion of the pieces of the material is not horizontal, but slightly upwardly inclined.

The convenience with which worn parts may be exchanged is apparent from the foregoing specification. Regarding the exchange itself the following considerations may be noted: As is known in the art, the specilic wear per unit weight of the material of the parts to each ton of the material treated is comparatively very low. This condition, however, could not fully be taken into account in conventional devices, as only a small percentage of the material of the parts exposed to wear could be utilized. A practically full utilization is now attained in the following manner:

The

protective layer

7 or 7 on the distributing plate 1 can be dimensioned so that its thickness will be proportional to the wear. The crushing pins are subjected only to wear on their upper freely exposed parts. By changing them from deep pockets 30 into more shallow pockets 31 their useful life can be prolonged. The remaining pin stubs can be joined by butt-welding to new pins of original length. The welding seams of such repaired pins are preferably placed so that they are positioned in the zone of wear in order to leave the unworn ends for the next welding. The protective ring 9 of the pin carrier 2 can be removed after removal of the pins and reversed, or exchanged if necessary. The diameters of this ring 9 and of the protective layer 7 can be chosen so that both parts can be cut without waste from one plate.

Itwill be noted that in the construction of this new impact mill any additional wearing or wear causing parts, such as screw and rivet heads and the likeI are entirely or almost entirely absent at least in the disintegrating zone of the device.

Instead of constructing the distributing disc or plate 1 and the rotary carrier 2 as separate and independently driven parts, the said plate may be integral with the said carrier. This simplifies the construction in so far as the shaft 3 and its driving means are then not required. Both, the distributing plate and the crushing pins Would rotate in the same sense and at the same speed, but for certain disintegrations such arrangement is quite workable and useful. Fig. 5 shows such an arrangement. According to this ligure, rotary carrier 2 and distributing disc are structurally united to form a distributing carrier 2 driven by pulley 15. The operation of this exemplification of the invention is obvious from the previous description.

It is to be understood that the invention is not intended to be limited to the embodiment which has been described and illustrated, but that any deviations to suit convenience or requirements may be made within the scope and meaning of the now following claims.

What we claim is:

1. A mill for disintegrating solid material in piece form comprising a housing including a disintegrating chamber and a discharge chute communicating with said chamber, a vertical rotary shaft within the housing, a distributing disc within said chamber tixedly seated upon the shaft, feed means for feeding pieces of the material to be disintegrated upon said disc for distribution by centirfugal force upon rotation of said shaft and disc, a rotary carrier disposed coaxially with said shaft, drive means for rotating said carrier, a plurality of crushing pins supported by said carrier in a ring arrangement radially spaced apart from the circumference of said disc, an inner impact sleeve disposed within said chamber above said disc coaxially therewith and having a diameter intermediate to the diameter of the pin ring and the rotational axis of the shaft, the lower edge of said sleeve being situated above the throw-ofr` zone of the disc and an outer impact sleeve disposed within said chamber above said disc encompassing the disc and the inner sleeve and having a diameter larger than the diameter of the pin ring, the said outer sleeve depending below the throw-olf zone of the disc, the said pins protruding above the disc and into the annular space defined between said sleeves whereby the centrifugally thrown-off pieces strike in free flight first said pins for crushing thereby and then said sleeves for disintegration by the impact therewith, the material being finally dischargedA in disintegrated form through said chute.

2. A mill according to claim l, wherein a cover forms a top wall of said housing, the said impact sleeves depending from said cover into said chamber and wherein the said feed means comprise a hopper extending through said cover into the chamber.

3. A mill according to claim 1, wherein the said radial spacing between the pin ring and the circumference of the disc is larger than the maximum size of the pieces to be disintegrated for effecting a free flight'of all the pieces before striking the crushing pins.

4. A mill according to claim 1, wherein the upper level of the disc is situated above the upper level of said pin carrier.

5. A mill according to claim 1, wherein the material receiving side of said disc is upwardly slanted in radial direction for lifting in the throw-off zone of the disc toward said outer impact zone.

6. A mill according to claim 1, wherein the said feed means are slanted relative to the plane of said disc for feeding material thereupon in tangential direction.

7. A mill according to claim 1, wherein the said carrier is formed with circumferentially spaced axial bores, the said pins being inserted in said bores with a loose t and held therein by centrifugal force.

8. A mill according to claim 7, wherein a ring of wear resistant material is fitted upon said carrier, the said ring being formed with circumferentially spaced axial bores therethrough for passage of said pins, the said pins tting the ring bores with a tight t for securing the rings to the pins.

9. A millaccording to claim l, wherein the said carrier is formed with circumferentially spaced axial bores of different depth, the said pins being inserted in said bores with a loose lit and held therein by centrifugal force` 10. A mill according to claim 1, wherein the said carrier is formed with circumferentially spaced bores slanted relative to the axis of said shaft, the said pins being nserted in said bores with a loose tit and held therein by centrifugal force.

1l. In a mill for disintegratng solid material in piece form, in combination, a rotary horizontally disposed distributing disc, feed means for feeding material to be disintegrated upon said disc for distribution by centrifugal force upon rotation of said disc, a rotary carrier disposed coaxially with said disc, drive means for rotating said disc and said carrier, a plurality of crushing pins extending from said carrier in a ring arrangement radially spaced apart from the circumference of said disc, an inner substantially circular impact member disposed above said disc coaXially therewith and having a radius somewhat less than the radius of the pin ring, the said inner impact member ending above the throw-oil' zone of said disc, and an outer substantially circular impact member disposed above said disc encompassing the pin ring and the disc and having a radius larger than the radius of the pin ring, the said outer impact member depending below the throw-oli zone of said disc, the said pins protruding into the annular space defined between said circular impact members whereby the centrifugally thrown-off pieces strike in free flight first said pins for crushing thereby and then said impact members for disintegration by the impact therewith.

References Cited in the tile of this patent UNITED STATES PATENTS 1,641,445 London Sept. 6, 1927 2,009,957 Esch July 30, 1935 2,207,194 Gruenaler July 9, 1940 FOREIGN PATENTS 14,003 Great Britain June 15, 1909 30,346 Great Britain June 30, 1911 448,011 Germany Aug. 6, 1927 553,055 Germany lune 21, 1932 656,996 Great Britain Sept. 5, 1951 850,356 France Sept. l1, 1939 OTHER REFERENCES Serial No. 355,937, Nyiri (A. P. C.), published May 4, 1943.