[0001] This invention relates to rotary mineral breakers.
[0002] An example of an earlier form of rotary mineral breaker is described by United States
Patent No. 3970257. This specification describes a mineral breaker provided with a
rotor positioned within a housing. Material is fed into the rotor and flung at high
speed at the housing walls (which themselves become lined with material) and material
to material contact is largely responsible for the crushing action of the apparatus.
[0003] The nature of this apparatus is such that there are severe mechanical stresses and
wear problems which must to be accommodated by adequate design. Vertical and horizontal
surfaces are subject to wear and these surfaces must be protected.
[0004] US Patent No. 4586663 addresses the problem of wear on vertical tip surfaces. The
same if not a more severe wear problem applies to horizontal surfaces. There are a
number of problems with the aforementioned constructions with respecto which solutions
are not readily apparent. The rotors are subject to extreme conditions of wear and
mechanical stress as would be appreciated from an understanding of the functions of
same. Because of the extreme mechanical forces which the rotors must withstand, it
was previously assumed that strong tension resistant materials must be used for the
top, bottom and sides of the rotors. Subsequently rotors built to date have been constructed
as a one piece cage with the only access to wear parts being via an upper inlet port
or outlet ports at the sides of the rotor. Because of poor access protective linings
for the upper and lower internal surfaces of the rotor have been provided in pieces
and removed and fixed via the very limited access provided by the inlet and outlet
ports.
[0005] The sides of the rotors are subject to constant frictional contact with the material
to be crushed and seams on the side walls of the rotor should be avoided if possible
as such tend to become a focus for wear. It is also desirable that the rotor outer
surfaces be as smooth as possible with minimal protrustion.
[0006] It is an object of the present invention to provide improvement to rotor construction
for rotary mineral breakers of the kind described.
[0007] Further objects and advantages of the present invention will become apparent from
the ensuing description which is given by way of example.
[0008] According to one aspect of the present invention there is provided a rotor for a
mineral breaker said rotor being of a generally drum-shaped configuration and arranged
to be rotated about a substantially vertical axis said rotor having a substantially
centrally positioned entry port in the upper surface thereof and at least one outlet
port in the wall thereof so that material fed into the entry part is able to escape
from the moving rotor via the said at least one outlet port, said rotor further comprising
a detachable top plate which covers substantially all of the exposed upper internal
surfaces of the rotor, said top plate being supported by side walls of the rotor.
[0009] The sides and base of the rotor can be fabricated from a material having a comparatively
superior resistance to tensile forces relative to the qualities of the material from
which the top plate is formed.
[0010] The uppermost regions of the side walls of the rotor can be provided with a rim providing
an internal ledge to which outer peripheral edges of the top plate can be removably
fixed.
[0011] The rim can be defined by an inwardly directed ring which extends from the sides
of the rotor and which provides means by which outer peripheral edges of the top plate
can be fixed and in addition enhances the strength of the rotor adjacent the top plate
providing resistance to forces acting at a tangent or radially to the sides thereof.
[0012] The said at least one outlet port is flanked by inwardly directed deflector plates
and wear tips.
[0013] The top plate can have a number of apertures therein to accommodate fixture members
and is fixed to the ledge by said fixture members in at least three positions and
is rotatable from one fixed position to another.
[0014] The rotor may include a base member protected by a lower wear plate which covers
substantially the whole of the base member.
[0015] The lower wear plate can be fixed to the base of the rotor by a centrally positioned
plug.
[0016] According to a further aspect of the present invention there is provided a top plate
for a rotor for a mineral breaker as aforesaid, said top plate having a lower surface
lined or comprising of a wear resistant material.
[0017] According to yet a further aspect of the present invention there is provided a lower
wear plate for a rotor, said lower wear plate having an upper surface lined or comprising
of a wear resistant material.
[0018] Aspects of the present invention will now be described by way of example only with
reference to the accompanying drawings in which:
Figure 1: is a plan view of a typical rotor assembly with the top plate removed in accordance
with one aspect of the present invention, and
Figure 2: is a cross section of a full assembly of the rotor of Figure 1, and
Figure 2A: shows how the top plate of the rotor of Figure 1 is fixed to the side walls, and
Figures 3 & 4: respectively are part plan and sectional views of a bottom wear plate for the rotor
of Figure 1, and
Figures 5 & 6: respectively are plan and sectional views of a rotor plug for the rotor of Figure
1 which fixes the bottom wear plate.
[0019] Firstly, with respect to Figures 1 and 2 of the drawings a rotor generally indicated
by arrow 1 comprises a circulat base 2, side walls 3 extending from the base and a
top plate generally indicated by arrow 4 which is removably fixed to the sides 3.
The base 2 is mounted on a substantial sleeve 5 which includes an inner bearing 6
and a plate 7. The plate 7 is fixed to the baring 6 by bolts The base 2 mounts a lower
wear plate generally indicated by arrow 8 which is secured in position by a central
plug generally indicated by arrow 9. Securement of the lower wear plate 8 is reinforced
by the positioning of rotor tips 10 and trail plates 11, the functions of which are
described in the aforementioned prior art references.
[0020] The rotor illustrated is provided with a strengthening or hoop ring 12.
[0021] The top plate 4 (hereinafter referred to as the upper wear plate) is an annular member
having a central aperture 13, and a stepped outer flange 14. The upper surface 16
of the wear plate is somewhat scolloped whilst the lower surface is provided with
a horizontal portion 17 leading to a diverging portion 18 adjacent the aperture 13.
Material entering the rotor via aperture 13 is dispatched via outlets 3A flanked by
the rotor tips 10 and trail plates 11.
[0022] The sides 3 of the rotor 1 are provided with a plurality of countersunk bolt holes
15 so that bolts 12A can be used to secure the upper wear plate 4 can be revolved
by sector to maximise life of the wear plate.
[0023] Figures 3 and 4 of the drawing illustrate one possible form of lower wear plate 8.
The wear plate is a simple annular ring having a stepped internal bore 19 and an outer
peripheral edge 20 with a number of notches 21 which accommodate arcuate extending
portions of vertical tips 10 and trail plates 11. The lower wear plate 8 is provided
with nine notches 21, three more than the total number of tips and trail plates and
can be revolved by sector to maximise the life of the wear plate. Access to the bottom
wear plate is provided by removing of the top wear plate 4 and rotor plug member 9.
[0024] Figures 5 and 6 of the drawings illustrate one possible form of plug member 9. The
plug member 9 is generally frusto-conical in shape giving a dome-like upper surface
22, a stepped edge 23, a central aperture 24 and a lowr flange 25. Figure 1 illustrates
the inter-relationship between the member 9, the bottom wear plate and parts beneath
it. A bolt single 26 secures the member in position.
[0025] By preference the base 2, walls 3 and ring 12 are fabricated from a tensile material
such as mild steel, and the top and bottom wear plates and distributor plates and
manufactured from a wear resistant material such as cast-iron. Other materials may
be used to form the wear plates. The welding symbols indicate the appropriate metal
to metal seams.
[0026] Modifications to the construction described may include using planar top surfaces
of the rotor side walls as a support for the peripheral edges of the top plate and
making the side walls sufficiently sturdy to cope with anticipated stresses during
use. Such an arrangement would create a side seam but may be a practical possibility
if the seam was protected by a sealant, such as a silicone sealant.
[0027] Whilst the top plate and lower wear plate are likely to be case in ferrous materials
it is anticipated that synthetic materials such as nylon, plastics or ceramics may
provide an option for either, particularly the lower wear plate which is non-structural.
[0028] It will be apparent that the present design, providng as it does access to the interiors
of the rotor from above, has many advantages over existing side access rotors, including:
- increased ease of entry for maintenance purposes,
- increased design flexibility
- the provision of one-piece wear plates for areas within the rotor previously protected
by wear a number of individual wear plates.
[0029] Aspects of the present invention have been described by way of example only and it
will be appreciated that modifications and additions thereto may be made without departing
from the spirit or scope thereof.
1. A rotor (1) for a mineral breaker said roto (1) being of a generally drum-shaped
configuration and arranged to be rotated about a substantially vertical axis said
rotor (1) having a substantially centrally positioned entry port (13) in the upper
surface thereof and at least one outlet port (3A) in the wall (3) thereof so that
material fed into the entry port (13) is able to escape from the moving rotor via
the said at least one outlet port (3A), said rotor further comprising a detachable
top plate (4) which covers substantially all of the exposed upper internal surfaces
of the rotor, said top plate (4) being supported by side walls (3) of the rotor.
2. A rotor (1) for a mineral breaker as claimed in claim 1 wherein the sides (3) and
base (2) of the rotor are fabricated from a material having a comparatively superior
resistance to tensile forces relative to the qualities of the material from which
the top plate (4) is formed.
3. A rotor (1) for a mineral breaker as claimed in claim 1 or claim 2 wherein the
material from which at least lower surfaces of the top plate (4) are formed is selected
to provide wear resistance.
4. A rotor (1) for a centrifugal mineral breaker as claimed in any one of claims 1
to 3 wherein the uppermost regions of the side walls (3) of the rotor are provided
with a rim providing an internal ledge to which outer peripheral edges of the top
plate (4) can re removably fixed.
5. A rotor (1) for a mineral breaker as claimed in claim 4 wherein the rim is defined
by an inwardly directed ring (12) which extends from the sides of the rotor and which
provides means by which outer peripheral edges of the top plate (4) can be fixed and
in addition enhances the strength of the rotor adjacent the top plate (4) providing
resistance to forces acting at a tangent or radially to the sides thereof.
6. A rotor (1) for a mineral breaker as claimed in any one of claims 1 to 5 wherein
said at least one outlet port (3A) is flanked by inwardly directed deflector plates
(11) and wear tips (10).
7. A rotor (1) for a mineral breaker as claimed in any one of claims 4 to 6 wherein
the top plate (4) has a number of aperture (15) therein to accommodate fixture members
and is fixed to the ledge (12) by said fixture members in at least three positions
and is rotatable from one fixed position to another.
8. A rotor (1) for a mineral breaker as claimed in any one of claims 1 to 7 including
a base member (2) protected by a lower wear plate (8) which covers substantially the
whole of the base member (2).
9. A rotor (1) for a mineral breaker as claimed in any one of claims 1 to 8 wherein
the lower wear plate (8) is fixed to the base (2) of the rotor by a centrally positioned
plug (9).
10. A top plate for a rotor (1) for a mineral breaker as claimed in any one of claims
1 to 9 said top plate (4) having a lower surface lined or comprising of a wear resistant
material.
11. A lower wear plate (8) for a rotor (1) as claimed in any one of claims 1 to 10,
said lower wear plate (8) having an upper surface lined or comprising of a wear resistant
material.