Abstrict This invention relates to replaceable wear resistant components
for rotary impact crushers and more particularly to the wear resistant
assemblies at the outlets from the crusher rotor the outlet trailing
edge main wear tip comprises a backing plate having secured to its
forward end a wear resistant assembly forming a step which will
be inwardly directed in use with respect to the rotor outlet the
step being sufficient to cause a build up behind the step of material
being crushed to form a protective lining against the inner wall
of the rotor.
Claims What I claim as new and desire to secure by letters patent is:
1. A main wear tip for an outlet of a rotary impact crusher rotor
comprising:
a backing plate having a forward end;
a wear resistant assembly secured to the backing plate forward
end forming an inwardly directed step which is with respect to the
rotor outlet, the step having sufficient size to cause autogenous
build up of material being crushed behind the step and to form a
protecting lining against an inner wall of the rotor, the wear resistant
assembly including a carrier block from which projects hard metal
tips.
2. The main wear tip of claim 1 in which the wear resistant assembly
has a lip opposite the step which lip is shaped to engage and protect
a trailing edge wall of the rotor outlet.
3. The main wear tip of claim 1 in which the hard metal tips are
secured in slots in the carrier block which slots are inclined towards
the step at an angle of about 45.degree. to the plane of the backing
plate.
4. The main wear tip of claim 3 in which the hard metal is tungsten
carbide brazed into position.
5. A main wear tip for an outlet of a rotary impact crusher rotor
comprising:
a backing plate having a forward end; and
a wear resistant assembly secured to the backing plate forward
end forming an inwardly directed step which is with respect to the
rotor outlet, the step having sufficient size to cause autogenous
build up of material being crushed behind the step and to form a
protecting lining against an inner wall of the rotor;
wherein the main wear tip is made in two inter-changeable vertical
halves.
6. A main wear tip for an outlet of a rotary impact crusher rotor
comprising:
a backing plate having a forward end; and
a wear resistant assembly secured to the backing plate forward
end forming an inwardly directed step which is with respect to the
rotor outlet, the step having sufficient size to cause autogenous
build up of material being crushed behind the step and to form a
protecting lining against an inner wall of the rotor;
wherein the main wear tip is fitted against an inner face of a
rotor wall and wherein a back up tip is secured against an outer
face of the rotor wall.
7. The apparatus of claim 6 wherein the wear resistant assembly
has a lip opposite the step which lip is shaped to engage and protect
a trailing edge wall of the rotor outlet, and in which the back
up tip has a leading edge chamfered inwardly and located against
the lip.
8. The apparatus of claim 6 in which the main wear tip is secured
to the rotor by bolts passing through the main wear tip, the rotor
wall and back up tip.
Description THIS INVENTION relates to rock crushers wherein a feed of rock
is accelerated and caused to strike a breaker wall to comminute
the rock.
BACKGROUND TO THE INVENTION
The type of crusher is well known and this invention applies particularly
to the kind having a rotor driven about a vertical axis. A feed
of rock is caused to fall axially into the rotor to discharge radially
therefrom at high speed. This accelerated rock strikes the wall
of a crusher chamber around the rotor where it breaks into smaller
pieces which fall from the crusher chamber for collection and possibly
further treatment. It is to be understood that the term "rock"
as used in this specification is to be interpreted as including
any material which may be broken from larger to smaller pieces in
the manner described.
In the very nature of things these crushers are subjected to conditions
of heavy wear due to abrasion and impact forces which occur. This
results in the need to use expensive hard wearing components and
also necessitates replacement of worn components.
Today the majority of rotary crushers of this type are self-lining
in that the rock being crushed forms a lining on the crusher chamber
wall and against which feed material is discharged to be broken
into smaller pieces while also breaking the pieces forming the lining.
During use this lining is self-replacing and it is desirable that
as much of the surface of the crusher that is subject to wear be
made to have this automatic formation of rock lining as possible.
Also it is obviously desirable to have the components subjected
to wear easily replaceable. These are particularly the rotor exit
and top and bottom plate linings and the ring feed inlet to the
rotor.
Access to wear-prone parts for inspection is, with known units,
difficult to achieve and maintenance inspection is virtually impossible.
This is undesirable as work on crushers of the type referred to
is frequently undertaken by unskilled labour.
The object of the present invention is to provide a crusher of
the above type which is effective in use and which can be easily
maintained and repaired when necessary.
SUMMARY OF THE INVENTION
According to this invention there is provided an inlet trailing
edge main wear tip for a rotary impact crusher rotor comprising
a backing plate having secured to its forward end a wear resistant
assembly forming a step. The assembly is inwardly directed in use
with respect to the rotor outlet. The assembly is sufficient to
cause a build up behind the step of material being crushed to form
a protective lining against the inner wall of the rotor and in which
the wear resistant assembly has a lip opposite the step which lip
is shaped to engage and protect the trailing edge wall of the rotor
outlet. The wear resistant assembly includes a carrier block from
which project hard metal tips. The hard metal tips are secured in
slots in the carrier block which slots are inclined towards the
step at an angle of about 45.degree. to the plane of the backing
plate and in which the hard metal is tungsten carbide brazed into
position.
A further feature of the invention provides for the outlet trailing
edge main wear tip for a rotary impact crusher rotor in which the
main wear tip is made in two interchangeable vertical halves.
Still further, there is provided for an outlet trailing edge wear
tip assembly for a rotary impact crusher rotor comprising a main
wear tip, to be fitted against the inner face of the rotor wall,
and a back up tip to be secured against the outer face of the rotor
wall. The back up tip has a leading edge chamfered inwardly and
located against the lip of the main wear tip. The outlet trailing
edge wear tip assembly is secured to the rotor by bolts passing
through the main tip, the rotor wall and back up tip.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages and features of the invention are described with
reference to preferred embodiments which are intended to illustrate
and not to limit the invention and in which:
FIG. 1 is a vertical cross-section through the impact chamber;
FIG. 2 is a plan of the crusher;
FIG. 3 and 4 details of the inspection door;
FIG. 5 an oblique view of the inlet chute;
FIG. 6 an oblique view of the rotor;
FIG. 7 a detail of the wear tip assembly;
FIG. 8 a detail of the lower rotor plate liner; and
FIG. 9 a detail of the feed ring.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
WITH REFERENCE TO THE DRAWINGS
Although a specific embodiment of the invention will now be described
with reference to the drawings, it should be understood that the
embodiment shown is by way of example only and merely illustrative
of but one of the many passible specific embodiments which can represent
applications of the principles of the invention. Various changes
and modifications, obvious to one skilled in the art to which the
invention pertains, are deemed to be within the spirit, scope and
contemplation of the invention as further defined in the appended
claims.
As illustrated in the drawings the crusher 1 has a rigid supporting
stand 2 carrying a box-like frame 3.
On the frame 3 is mounted the crusher chamber 4 in which is centrally
located the rotor assembly 5. Also centrally located with respect
to the crusher chamber and co-axial with the rotor assembly 5 is
feed chute 6 having an axial outlet 7 in which is supported an inlet
tube 8 opening into the feed ring of the rotor assembly 5. The feed
chute also has a plurality of outlets 7A through the wall thereof
spaced above the upper end of the inlet tube 8. The feed chute 6
rests on retaining lugs in an upward extension 9 from the crusher
chamber 4.
Bracing webs 10 extend from the extension 9 to the outer periphery
of the top of the crusher chamber 4. These webs 10 have holes therein
to facilitate lifting the crusher chamber 10 from the supporting
frame 3 to which it is releasably secured preferably by bolting.
The frame 3 also provides part of the wall 11 of a collection compartment
12 which has large outlet openings 13 in the floor thereof enabling
crushed material to fall into discharge chutes 14 from whence the
material can be carried by a suitable conveyor belt arrangement
(not shown). The discharge chutes 14 are made to accommodate the
usual necessary inclination of the conveyor belt arrangement.
The discharge chutes 14 are located on opposite sides of the rotor
drive shaft 15 which passes through the collection compartment 12
within a suitable shrouding 16. The top of compartment 12 is open
but the shrouding 16 is supported by a spider indicated at 17.
The drive shaft 15 is driven by a suitable motor 18 through a vee-belt
drive. In larger installations and where using an electric motor
drive it is preferable to use a pair of motors opposite each other
to drive the drive shaft 15 in unison. Each motor will be mounted
on a cradle 19 rigidly secured to the frame 3. Adjustment bolts
20 enable the tension of the belt drive to be easily and accurately
controlled.
The shrouding 16 will preferably house a replaceable unit which
will include bearings and seals together with appropriate lubrication
so that repair of any worn bearings can be easily effected by replacing
the entire unit. The unit replaced can be stripped and repaired
where appropriate workshop facilities are available.
In the example illustrated the crusher chamber 4 is square. It
has a circular opening 21 with an inwardly extending flange 22.
This flange 22 is located so that there is a space 23 between the
outside of the feed chute 6 through which a secondary flow of material
to be crushed can fall from the outlets 7 over the edge of the rotor
assembly 5 in the crusher chamber 4. The free end of the flange
22 carries an outwardly directed circumferential lip 24 which is
arranged to lie on substantially the same plane as the upper edge
of the outlets from the rotor assembly 5.
The outlet 25 from the crusher chamber 4 is of larger diameter
than the inlet opening 21 and provides an annular space between
the floor 26 of the chamber 4 and the rotor assembly 5 through which
material subjected to the crushing operations can pass into the
collection compartment 12. The edge of the outlet 25 carries an
upstanding rim 27.
Gusset plates 28 spaced apart at regular intervals around the crusher
chamber 4 extend between the rim 27 and the outer wall of the crusher
chamber 4 at a height level with the lip 24.
While the crusher chamber above described is square in shape it
will be understood that this is not essential. It could be made
any other convenient shape but is easily fabricated to square shape
from heavy gauge steel plate.
Part of one side wall of the crusher chamber 4 is formed as an
inspection door 29. The door 29 is carried on heavy supporting hinges
30 on the outside of chamber 4 and the securing bolt assembly 31
is of similar heavy construction with a removable bolt 32 engaging
in vertical holes provided to aligned lugs 33 carried by the door
and the outer wall of chamber 4.
The door 29 carries inwardly directed gusset plates 34 extending
from each side of the door and are arranged so that when the door
29 is in the closed position these gusset plates 34 will lie one
against each of a pair of adjacent gusset plates 28 in the crusher
chamber 4. The gusset plates 34 do not extend the full length of
those 28 and stop short of the rim 27. Top and bottom plates join
the upper and lower edges of the gusset plates 34.
The door assembly forming part of the crusher chamber wall has
the great advantage that inspection and maintenance of the wear
parts of the rotor assembly 5 is greatly facilitated compared with
other comparable rotary crushers. Part of the crushing bed (described
below) which forms from rock being crushed against the wall of the
chamber 4 during use remains intact when the door is open. The door
extending the full height of the chamber 4 enables ready inspection
of and access to the wear parts in the rotor assembly where many
of these parts can be replaced and welding operations conducted
without the necessity to remove the rotor assembly 5. All the wear
parts in the rotor assembly which are commonly repaired or replaced
can be reached either through the door or by simply lifting the
inlet tube 8 and feed chute 6 from the top of the crusher 1.
The wide access areas provided in the crusher construction according
to this invention also enable proper supervision of repairs and
replacements to be undertaken.
The rotor assembly 5 consists of a rotor 35 which is constructed
to generally triangular shape in plan view. The rotor is a balanced
construction and equiangular. Outlet openings 36 are provided at
the apices of the trangular shape.
The rotor has upper and lower plates 37 and 38 spaced apart by
vertical side walls 39 and an inlet opening 40 made centrally through
the upper plate 37.
The lower plate 38 is adapted to be secured to the drive shaft
15 preferably in known manner using a taper lock coupling. A shaft
end cover in the form of a conical wear resistant component 41 is
fixed to the end of the shaft 15 so that material to be crushed
cannot come into contact with shaft assembly. This component 41
deflects the material fed into the rotor towards the outlets.
The rotor can conveniently be made of heavy gauge mild steel to
the outer surface of which is applied a hard facing material in
known manner.
To protect the inlet 40 the feed ring 42 is provided. This ring
42 fits into the inlet opening 40 and locking lugs 43 pass through
complementary notches 44 provided through the top plate 37 of the
rotor 35. Stops 45 are welded to the under surface of the top plate
37 against which lugs 43 abut to locate the feed ring 42 with respect
to the rotor 35 during use. The ring 42 is supported on the rotor
top plate 37 by a peripheral flange 46 on the feed ring. The part
47 of the feed ring 42 extends around the outlet from the inlet
tube 8.
The lower part 48 of the feed ring extends below the top plate
37 of the rotor 35 and has recesses 49 which are located opposite
the rotor outlets 36. These recesses 49 have peripherally extending
notches 50 in their side walls and extend from the bottom of the
ring to below the flange 46. Complementarily shaped wear inserts
51 of slightly greater overall depth fit into the recesses 49 and
abut against the wall of the inlet opening 40 through the top plate
37. These inserts 51 have been found in practice to abort most of
the excessive wear on the feed ring during use. Thus their replacement
from time to time avoids the necessity for the replacement of the
complete feed ring and this replacement can be affected by removing
the feed chute 6 and inlet tube 8. Also making the inserts of greater
depth than the notches to extend below the remainder of the feed
ring accommodates to a further degree the excessive wear which takes
place over these areas.
The internal surfaces of the upper and lower plates 37 and 38 are
also provided with wear resilient liners. A study of the wear pattern
with the rotor of this invention has enabled the liners to be made
in two approximately radially extending parts 52 and 53. The parts
53 are fixed to the plates 37 and 38 preferably by welding while
the parts 52 are removable. The parts are shaped so that the edge
of part 53 adjacent part 52 is undercut to support a projecting
tapered edge 54 along the length of the part 52.
The opposite edge 55 of part 52 has a shoulder 56 which engages
a support 57 which is welded to extend from the inside of the rotor
35. These supports 57 extend the full length of the part 52 from
the top plate lining because the parts 52 can be fitted by sliding
them into position from the inlet opening against the under surface
of the top plate 37. However the conical component 41 protecting
the end of the drive shaft 15 prevents the lower parts 52 being
inserted in a similar manner.
The supports 57 are made as a plurality of separate members and
the shoulders 56 of the parts 52 are notched in such a manner that
the parts 52 can be fitted by tilting the part 52 to have its tapered
edge engage under the part 53 and then allow the part 52 to lie
against the bottom plate by passing the supports 57 through the
notches in the shoulders 56. The part 52 can then be slid radially
outwardly to bring it into its required position during use. The
notches in the shoulders and the supports will be positioned to
enable the above movements to be achieved.
To remove the parts 52 the movements described are reversed.
The outlets 36 from the rotor 35 each include a wear tip assembly
indicated generally at 58. This assembly is fitted to the trailing
edge of the outlet opening and extends the full height of that opening.
The main wear tip 59 is made in two parts, one above the other only
one part of which is indicated in FIG. 7. Each part of wear tip
59 consist of a backing plate 60 to which is welded a carrier block
61 to project from one end of the plate 60 and to form a step which
extends beyond the surface of the plate 60. A slot is formed in
the block at an angle of about 45.degree. to the plane of the plate
60 and tungsten carbide tips 62 are brazed into position in the
slots. The plate 60 is perforated to accommodate mounting bolts.
The plate 60 is positioned against the inner wall of the rotor
and on the outer face of the rotor there is provided a heavy back
up tip 63. This has a chamfered leading edge 64 which locates behind
the block 61 with the rotor plate clamped by bolts extending through
the mounting and rotor plates and back up tip 63.
The liner parts 52 have their radially outer ends set away to accommodate
the wear tip 59.
The leading edge 65 of the outlet opening 36 is provided with a
radially inwardly directed lip 66. This lip is tapered from one
end to the other and, while it is subjected to little wear during
use the taper has the effect of controlling the discharge from the
opening 36 with which it is associated. When the wider part of the
lip 66 is against the lower plate 38 of the rotor the main discharge
stream is raised. When the lip is reversed the main discharge takes
place at a lower level. In this way the action of the rotor can
be controlled to give the best discharge with least wear depending
on material being crushed and other prevailing operating conditions.
In use the crusher operates in a well known manner by the rotor
being driven to discharge rock fed axially therein against the wall
of the crusher chamber. A lining of rock builds up automatically
against the wall of the chamber into a circular shape and this lining
of rock provides the wall against which rock thrown from the rotor
is crushed. The wall is continually worn away and replaced.
An important feature of the invention is the provision of the lip
24 and the rim 27. These components ensure that the build up of
rock in the crusher chamber extends completely around the crusher
chamber wall from the lip 24 round to the rim 27. The effect of
this is not only to prevent wear of the chamber wall but also results
in the crushed rock discharging from the chamber in a predominantly
downward direction towards the outlet 25 extending around the bottom
of the rotor. This materially reduces the wear on the rotor.
As the axial feed is built up rock also flows out of the openings
through the side wall of the feed chute 6 where it builds up a ramp
inlet for excess material which flows past the flange 22 and through
space 23. From there it drops downwardly adjacent the edge of the
rotor to be violently contacted by the rock being discharged from
the rotor at high speed. This gives the known additional crushing
action which is obtained by having two feeds into the crusher.
The design of the crusher according to this invention is made so
as to use as far as possible an automatic lining of wearing parts
with rock being crushed.
Particular reference is made to the step formed by the carrier
block 61 which traps rock behind the trailing edge of the outlet
opening 36 thus confining wear to the main wear lips 59. As described
these lips 59 are made in pairs. Most of the wear takes place near
the middle of the outlet and as the lips become worn their positions
may be reversed so that complete use of the expensive tungsten material
can be made before new wear lips 59 need be fitted to the crusher.
The build up behind the lips also protects the supports 57 for the
liner parts 52 against wear.
The triangular shape to the rotor not only reduces the material
used and weight of the rotor but also keeps wear of the hard faced
outer surfaces to a minimum. Also in the event of a build up of
material in the crusher chamber causing rapid excessive wear of
the rotor to an extent equivalent to the thickness of the side wall
of the rotor, there is no danger of the rotor disintegrating. With
a circular rotor this danger is inherent because once wear of this
nature takes place the rotor upper plate is no longer connected
to the lower plate. This can lead to disastrous results to the crusher
and danger to the operators.
The draught caused by the rotor tends to cause air to be blown
back through the crusher outside the feed chute 6 and to minimise
this undesirable effect vanes 67 are fitted near the top of the
feed chute to deflect this air flow back into the crusher.
Also the rotor is caused to rotate in an anticlockwise direction
and this together with the centrifugal forces exerted by the rotor
movement ensure that the feed ring 42 with its wear inserts 51 and
the liner parts 52 are held in position during use without securing
means. This further facilitates repair and replacement of these
parts by unskilled labour.
The complete crusher is of simple but effective construction and
has been found to be both effective and durable even under extremely
arduous conditions. |