GB2088746A - Mineral breakers - Google Patents

Abstract

A mineral breaker including a passageway 15 through which mineral to the breaker is fed, a pair of side by side rotatable breaker drums 11, 12 located within the passageway 15 and each having rows 17 of breaker teeth 16, the breaker teeth of one drum co-operating with the breaker teeth of the other drum to prevent oversized material passing between the drums, the drums being arranged to rotate in opposite directions so that each drum directs mineral deposited on the drums away from the other drum toward an adjacent side wall 20, 21 of the passageway, each breaker drum co-operating with the adjacent side wall to break the mineral. The side walls are formed by plates 22, 23, having rows 33, 34 of teeth 35 and may be spring-loaded to prevent passage of tramp material. <IMAGE>

Description

SPECIFICATION Mineral breakers The present invention relates to mineral breakers and in particular mineral breakers capable of sizing mineral to small sized material.

It is a general aim of the present invention to provide a mineral breaker for sizing material down to say 2" average diameter or less, the breaker being compact in size yet capable of handling a large throughput of mineral.

According to one aspect of the present invention there is provided a mineral breaker including a passageway through which mineral to the breaker is fed, a pair of side by side rotatable breaker drums located within the passageway and each having rows of breaker teeth, the breaker teeth of one drum co-operating with the breaker teeth of the other drum to prevent oversized material passing between the drums, the drums being arranged to rotate in opposite directions so that each drum directs mineral deposited on the drums away from the other drum toward an adjacent side wall of the passageway, each breaker drum co-operating with the adjacent side wall to break the mineral.

Preferably each side wall includes a row of teeth which co-operate with the teeth on the adjacent drum to break mineral to the required size. The terminal edge of each tooth on each side wall is preferably arranged to be slightly below the plane containing the axes of rotation of the drum.

Advantageously each side wall is curved inwardly above its adjacent drum.

Other aspects of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of an embodiment according to the present invention; Figure 2 is a sectional view taken along line Il-Il of Fig. 1; Figure 3 is a schematic side view similar to Fig. 1 showing one side only of the breaker incorporating a modification; Figure 4 is a perspective view, partly broken away, of the spring loaded support assembly shown in Fig. 3.

A mineral breaker 10 includes a pair of rotatable breaker drums 11, 1 2 which are respectively rotatably mounted in a housing 14.

The housing 1 4 includes a passageway 1 5 through which mineral to be broken is fed.

The drums 11, 1 2 extend across the passageway 1 5 and have breaker teeth 1 6 which are arranged to prevent oversized mineral passing by the breaker drums. In this respect the breaker teeth 1 6 of each drum are arranged in circumferentially extending rows 17, which are spaced along the length of each drum, the rows 1 7 on one drum being axially offset from the row 1 7 on the other drum to enable the rows of teeth 1 6 on one drum to penetrate between the rows of teeth on the other drum as seen in Fig. 2. In Fig. 1 the rows of teeth 1 6 are shown schematically and some rows 1 7 have been excluded from the Figure for the sake of simplicity.The teeth on one drum extend to close proximity with the periphery of the other drum as seen in Fig. 2 so that oversized mineral is prevented from passing between the drums.

The side walls 20, 21 of the passageway 1 5 are formed by plates 22, 23 respectively and as seen in Fig. 2 the teeth 16 are arranged to extend to close proximity with the inner surface of plates 22, 23.

The plates 22, 23 are preferably rolled to provide an upper curved portion 22a, 23a respectively. Each curved portion 22a, 23a extends upwardly from just above the plane containing both axes of rotation of the drums.

Preferably each curved portion 22a, 23a has a center of curvature lying on a centre line passing between both drums 11, 1 2.

The plates 22, 23 are each mounted within the housing 1 4 by means of supporting brackets 26, 27 respectively which sit upon the upper edge of side walls 28, 29 of the housing and are bolted thereto. A row of bolts (not shown) extending along the lower marginal portion of each plate 22, 23 serves to connect the lower portion of each plate to a respective side wall 28, 29. Plates 22, 23 may therefore be easily removed from the housing 1 4 by removal of the bolts to enable the plates to be lifted out of the housing.

Plates 22, 23 are peferably secured to their respective support brackets by welding. The plates 22, 23 are conveniently formed from any suitable metal or other material capable of withstanding the working conditions imposed thereon.

The upper surface of each bracket 26, 27 serves as a seat or a hopper 30 which guides mineral to be broken into the passageway 15.

Each plate 22, 23 is provided with a row 33, 34 respectively of teeth which rows extend along the length of each plate so as to extend along the length of the adjacent drum 11, 1 2 respectively.

Adjacent teeth 35 of each row are spaced from one another so as to be located between adjacent rows 1 7 of teeth on the adjacent drum. The teeth 35 extend toward the periphery of the adjacent drum so that its terminal edge 35a is spaced therefrom by a distance approximately equal to the desired sizing of mineral which is to be created. The upper surface 36 of each tooth 35 is inclined downwardly and adjacent teeth 35 co-operate with teeth 1 6 passing therebetween to break mineral. The trailing edge 37 of each tooth is preferably inclined toward the associated plate 22, 23 to which it is attached at the steepest angle possible so as to reduce to a minimum the distance each tooth 1 6 has to travel between adjacent teeth 35.This is highly desirable as it reduces drag on the drums and reduces the tendency for blockages to occur.

The teeth 35 are preferably positioned in relation to the drums 11, 1 2 so that their terminal edge 35a is just below the plane containing the axes of rotation at the drums 11, 1 2. The teeth 35 conveniently formed from metal plating which is cut to shape and secured in position on the respective plate 22, 23 by welding.

In use mineral to be broken is fed to hopper 30 which directs the mineral into passageway 15 for deposit on the drums 11, 1 2 as shown by arrow A. The drums 11, 1 2 are rotated in opposite directions (drum 11 in an anticlockwise direction and drum 1 2 in a clockwise direction as viewed in Fig. 2) so that each drum directs mineral away from the other drum towards the adjacent plate 22, 23 respectively as shown by arrow B.

The teeth 1 6 on each drum bite into mineral trapped between themselves and the adjacent plate 22, 23 to break the mineral down into smaller pieces. As the teeth 1 6 move toward teeth 35 the spacing between teeth 1 6 and the adjacent plate 22, 23 decreases so that mineral riding on the back face 1 6a of leading teeth 1 6 are broken by the terminal edge 1 6 b of succeeding teeth. The space 16 c between leading and succeeding teeth 1 6 is such as to enable mineral pieces of the desired thickness to be accommodated therein so that they are delivered to teeth 35 which co-operate with teeth 1 6 to further break the mineral down to the desired sizing.There are thus two stages of breaking, a primary breaking region 40 wherein teeth 1 6 co-operate with the inner curved surface of plate 22, 23 respectively and a secondary breaking region 41 wherein teeth 1 6 co-operate with teeth 35 to effect further breaking of mineral.

In certain applications it is possible for material which wili not break to be mixed in with the mineral entering the breaker, for instance metal rods. Accordingly if such material enters the breaker it is possible for the material to jam between teeth 1 6 and 35 and so prevent rotation of the drums.

In order to accommodate for such an occurance the breaker may be modified as schematically illustrated in Fig. 3 wherein teeth 35 are mounted on supports 60 which are sli dably mounted in housings 61 attached to respective side walls 28, 29. The supports 60 are sprung biased to a projecting position as shown so that the teeth 35 carried thereby co operate with teeth 1 6 in the normal manner as described above. If unbreakable material, such as a metal rod, impinges on teeth 35, the degree of bias and angle of inclination of face 36 are chosen such that the metal rod causes the support to move to a retracted position to thereby allow the metal rod to pass without causing a seizure.

The construction of supports 60 and corresponding housing 61 is shown in greater detail in Fig. 4. In Fig. 4 two supports 60 are shown housed in a common housing 61. The number of supports 60 contained in the housing 61 and the length of housing 61 are chosen to suit the length of the breaker drums 11, 12.

Each support 60 is in the form of a box having a front wall 62. The teeth 35 are secured to the front face of wall 62 and a pair of guide rods 64 and a pair of bolt shafts 65 project rearwardly from the rear face of front wall 62. The rods 64 are slidably received in apertures formed in a rear wall 67 of housing 61 and the terminal ends of bolt shafts 65 project through wall 67 to receive nuts 69. A series of spring washers 70 are located on both rods 64 and are compressed to a desired amount between wails 62 and 67 by tightening of nuts 69. Each support 61 is provided with projections 72 for location in apertures 73 formed in the top and bottom walls 74, 75 respectively of housing 61.

The above described mineral breaker is capable of producing broken mineral which contains a high percentage of correctly sized mineral without producing excessive amounts of fines. The breaker is also capable of handling large throughputs of mineral. Additionally, the inlet 15ato passageway 15 is relatively large and thereby reduces the likelihood of mineral to be broken bridging thereacross.

It is envisaged that the above mineral breaker may be modified to perform different tasks. For instance the size of teeth 1 6 and 35, spacing between rows 1 7 may be varied as desired to give different sizing capabilities.

In this respect the drums 11, 1 2 are preferably of a similar construction to those described in our co-pending U.K. Patent Application No. 8021173 wherein teeth 16 are formed in longitudinal strips which are releasably secured to the body of the drum.

Additionally in cases where the required percentage of sized material is not critical it is possible to dispense with teeth 35 so that breaking takes place in the primary region only.

Alternatively, the curved portion of plates 22, 23 may be dispensed with in certain applications so that plates 22, 23 are basically planar. Breaking would then take place substantially only between teeth 1 6 and teeth 35. Such an arrangement including closely spaced teeth 1 6 and 35 could be used as a shredding machine for shredding slurries, for example as produced in coal mining for trans porting waste materials, thereby ensuring that solid material in the slurry is reduced to a desired size.

Claims (6)

1. A mineral breaker including a passa geway through which mineral to the breaker is fed, a pair of side by side rotatable breaker drums located within the passageway and each having rows of breaker teeth, the breaker teeth of one drum co-operating with the breaker teeth of the other drum to prevent oversized material passing between the drums, the drums being arranged to rotate in opposite directions so that each drum directs mineral deposited on the drums away from the other drum toward an adjacent side wall of the passageway, each breaker drum cooperating with the adjacent side wall to break the mineral.

2. A mineral breaker according to Claim 1 wherein each side wall includes a row of teeth which co-operate with the teeth on the adjacent drum to break mineral to the required size.

3. A mineral breaker according to Claim 2 wherein the terminal edge of each tooth on each side wall is arranged to be slightly below the plane containing the axes of rotation of the drums.

4. A mineral breaker according to Claims 2 or 3 wherein each side wall is curved inwardly above its adjacent drum.

5. A mineral breaker according to any of Claims 2 to 4 wherein the teeth associated with each side wall are movably supported on the associated side wall and biased to a projecting position so that they may be retracted against said bias when subjected to an excessive loading.

6. A mineral breaker substantially as described with reference to and as illustrated in the accompanying drawings.