Abstrict A single-roll crusher has a crushing roll formed with a plurality
of hammers and disposed above an anvil or breaker plate which can
form the bottom of a trough through which a conveyor passes to carry
the material to be crushed into the breaker and the crushed product
therefrom. The height of the central portion of the roll above the
anvil plate defines the maximum size of the material which can be
comminuted. To stabilize the rotation of the roll and yet permit
this distance to be relatively great, a pair of massive circular
spinning disks are mounted on the roll shaft coaxial with the roll.
The disks flank the channel through which the material passes.
Claims We claim:
1. A single-roll crusher, especially for coal and similar minerals,
comprising a housing, a bifurcated support pivotally mounted on
said housing, a crusher roll journaled on said support and provided
with a plurality of hammers, an anvil plate disposed below said
crusher roll and cooperating with said hammers to comminute mineral
pieces passing through a throad between said roll and said anvil
plate, and a pair of rotating disks mounted on the extremities of
said roll and flanking said hammers, said roll having a shaft journaled
on said support and forming the axis for said disks, said disks
resisting upward forces on said roll and imparting thereto a moment
of inertia positionally stabilizing same.
2. The single-roll crusher defined in claim 1 wherein said disks
define the lateral width of said throat and the distance between
said roll intermediate said disks and said plate is the height of
said throat.
3. The single-roll crusher defined in claim 1 wherein said housing
encloses said roll and has a pair of lateral walls, said lateral
walls being disposed between respective arms of said bifurcated
support and a respective one of said disks, said lateral walls being
formed with guide slots traversed by said shaft and enabling the
vertical displacement thereof, said disks covering said slots and
preventing the escape of comminuted material therethrough.
4. The single-roll crusher defined in claim 3 wherein said hammers
define an impact circle diameter and said disks have diameters at
least equal to said impact circle diameter.
5. The single-roll crusher defined in claim 4 wherein each of said
hammers is formed as a disk segment, said segments being disposed
in pairs offset by 180.degree. about the axis of said shaft.
6. The single-roll crusher defined in claim 5 further comprising
spacer rings separating said segments from one another.
7. The single-roll crusher defined in claim 6 wherein said disks
together have a mass of 5 to 80% of the total mass of said roll.
8. The single-roll crusher defined in claim 7 wherein said anvil
forms the base of a channel, said crusher further comprising a flight
conveyor for displacing mineral pieces along said anvil plate through
said channel.
9. The single-roll crusher defined in claim 8 wherein said support
has a pair of arms each provided with a respective journal block
and rotatably supporting an end of said shaft, said disks being
disposed proximal to said journal blocks.
10. The single-roll crusher defined in claim 9 further comprising
respective height adjustment means engaging each of said arms.
Description FIELD OF THE INVENTION
The present invention relates to a single-roll crusher for the
comminution of large pieces of mineral substances, especially coal
or like minerals. More particularly, the invention deals with improvements
in stabilizing the operation of a roll of a single-roll crusher
for mineral matter.
BACKGROUND OF THE INVENTION
A conventional through-feed single-roll crusher comprises a crusher
roll which may be formed with one or more hammers and is journaled
for rotation about a horizontal axis at a distance above a breaker
or anvil plate across which the mineral substances to be comminuted
are passed. The anvil can be formed by the base of a trough through
which a flight conveyor passes to entrain the mineral bodies into
the path of the hammers and to carry away the comminuted product.
In conventional systems of this type the roll is provided with
an eccentric counterweight to counterbalance the hammers. This counterweight
lies in the central portion of the roll between the flanks of the
channel through which the material is conducted and thus reduces
the clearance between the central portion of the roll and the anvil.
Since this clearance determines the maximum size of the material
which can be handled in the crusher or breaker, the disadvantages
of such systems will be apparent.
Furthermore, there have been conventional systems which have been
designed to absorb the upwardly directed reaction forces between
the upper portion of the crusher and the lower portion thereof with
shock absorber acting upon the crusher roll. These shock-damping
devices provide a floating support of the upper portion of the crusher
and therefore for the crusher roll upon the lower portion.
Such a floating suspension for the roll has been found to be disadvantageous
in various respects. Thus, when the stress is applied to the breaker
roll somewhat off center, the latter is subjected to uncontrollable
transverse forces which result in a wobbling operation of the roll.
A corresponding wobbling of the entire upper portion of the crusher,
upon which the roll is mounted, also is observed. The rotation of
the roll is thus frequently unstable and the crushing efficiency
is reduced or the product size will vary.
Finally, it will be apparent that the more cushioning is used in
supporting the crusher roll, the softer will be the impact for given
parameters of breaker roll operation and hence efficiency falls
off with increased cushioning by the shock absorber. The impact
of the roll, when the latter is suspended with shock absorbers,
must be relatively low in order to prevent high stresses from being
applied to the bearings in which the roll is journaled. This again
reduces the output and effectiveness of the crusher.
OBJECTS OF THE INVENTION
It is the principal object of the present invention to provide
an improved single-roll crusher in which the aforedescribed disadvantages
are avoided.
Another object of the invention is to provide a single-roll crusher
in which the upper portion of the crusher need not be suspended
by shock dampers or the shock absorber mounting of the roll can
be eliminated or minimized.
Still another object of the invention is to provide a single-roll
crusher capable of processing materials of large size without the
disadvantages of the earlier systems mentioned above.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter
are attained, in accordance with the present invention, in a single-roll
crusher in which the roll shaft forms the axis of rotation, a pair
of massive circular spinning disks which flank the hammers of the
roll in the region of the shaft ends.
According to the invention, therefore, a single-roll crusher comprises
a housing, a bifurcated support swingably mounted on the housing
about a horizontal axis and formed with the trunnions for a crusher
roll, a crusher roll journaled in these bearings about a horizontal
axis spaced from the pivot axis of the bifurcated support so that
as the free extremities of the arms of the bifurcated support are
raised and lowered, the height of the roll axis is correspondingly
varied, an anvil disposed below the crusher roll at a distance therefrom
which varies in dependence upon the position of the roll axis, a
conveyor traveling along the anvil for entraining large pieces of
coal or other mineral into the housing and past the roll and carrying
the comminuted product out of the housing which forms a trough having
an anvil as its floor, and a pair of circular disks forming flywheels
at each end of the hammer portion of the crusher roll. Advantageously,
these disks have a mass which is a substantial fraction of the mass
of the roll, e.g. between 5 and 80% of the mass of the roll.
According to a feature of the invention, the crusher roll is provided
with a central portion having a plurality of hammers projecting
outwardly from the periphery of the central portion and engageable
with the mineral matter in the channel defined between the inwardly
facing surfaces of the aforedescribed disks.
This arrangement has the advantage that it eliminates the need
for eccentric counterweights and shock-absorber supports for the
crusher roll and nevertheless allows the throat of the machine,
as measured between the central portion of the roll and the anvil,
to be considerable and thereby enabling large pieces to be processed
with ease. Furthermore, the impact circle diameter can be substantially
larger than in conventional systems.
These advantages are obtained because the outwardly disposed circular
diskks on the one hand resist the upwardly directed reaction forces
applied to the crusher roll and, on the other hand, because of their
high moments of inertia increase the impact energy and positional
stability of the crusher roll.
The rotating masses formed by the disks can be used fully to store
energy which is converted into impact energy in accordance with
flywheel principles. Since the large masses of these disks are located
at the ends of the shaft, even noncentral forces applied to the
roll do not adversely affect its stability.
Because the disks are located at the outer ends of the roll and
immediately adjacent the support bearings or trunnions, there is
a minimum loading of the latter. Any stresses developed between
the hammers and the disks are absorbed within the central portion
of the roll and are not transferred to the crusher housing. Damage
to the crusher housing is thereby precluded. The machine can therefore
be described as a circular disk breaker.
According to another feature of this invention, the two outwardly
disposed circular disks define the lateral flanks of the channel
through which the mineral material is passed. In this case the disks
not only protect the lateral walls of the housing, but since they
rotate in the direction of movement of the materials they reduce
the frictional drag on the material which otherwise would be applied
by the housing and increase the throughput through the system.
Advantageously the lateral walls of the housing are provided with
guide slots through which the shaft of the crusher roll extends
and in which the shaft is permitted to move on the bifurcated support.
The circular disks overlie these slots and prevent escape of the
comminuted material.
It has been found to be advantageous to have the diameter of the
circular disks at least equal to the impact-circle diameter so that
the circular disks constitute a large rotating mass. In this respect
it should be noted that the most preferred condition has the circular
disk diameter equal to the diameter of the impact circle defined
by the hammers on the roll.
According to yet another feature of the invention, the hammers
of the roll are constituted as disk segments with heads mounted
at the ends of the respective segments, the segments being provided
in pairs which are offset by 180.degree. from one another about
the axis of the crusher-roll shaft. This balances each hammer with
another. Between hammer segments we provide spacer rings which are
exchangeable, interchangeable or replaceable to vary the spacing
and positions of the hammers or pairs of hammers.
The free ends of the arms of the bifurcated support are vertically
adjustable by means of piston-and-cylinder devices which can be
connected to a height adjustment mechanism for varying the throat
of the machine as measured between the central portion of the crusher
roll and the anvil plate.
The system has the advantage that it permits the central portion
of the crusher roll to be of relatively small diameter and yet have
a large impact-circle diameter so that the capacity of the machine
or large bodies is increased. The upwardly directed reaction forces
are taken up by the circular disks and the latter also enhance the
deliverable impact energy. A maximum output is achieved with a minimum
of energy input. The system can be automatically adjusted to accommodate
larger or smaller pieces of the mineral and is generally simpler
and more efficient than earlier systems.
BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, features and advantages of the present
invention will become more readily apparent from the following description,
reference being made to the accompanying drawing in which:
FIG. 1 is a front-elevational view, partly in diagrammatic form,
of a single-roll crusher according to the invention;
FIG. 2 is a side-elevational view, partly broken away, of the crusher;
and
FIG. 3 is a plan view of the crusher of FIGS. 1 and 2.
SPECIFIC DESCRIPTION
In the drawing we show a single-roll crusher which comprises a
housing 20 formed with an inlet side 21 and an outlet side 22 and
traversed by a chain flight conveyor represented at 23. This conveyor
comprises flights 24 which are entrained by a chain 25 along opposite
surfaces of an anvil plate 6 mounted between the lateral walls 8
of the housing 20. The ends of flights 24 are guided in grooves
26 of guide bodies 27 which form a channel 28 for the material to
be comminuted. This channel has an effective width W and an effective
height H as will be described in more detail below.
The housing 20 is formed with reinforced supports 30 for a shaft
1 defining the pivot axis for a bifurcated support 2. The support
2 has arms 2a and 2b , each arm carrying a pedestal 2c secured by
reinforcing ribs 2d and mounting respective journal blocks 2e forming
trunnions for a breaker shaft 4. The shaft 4 extends horizontally
through the housing and is formed therein with a crusher roll 3
having an effective roll diameter d.
The crusher roll 3 is formed by a plurality of hammers 5 separated
by one or more spacer disks 13 the latter being replaceable and
exchangeable so that the positions of the hammers 5 can be varied.
The hammers sweep through an impact circle 5a having a diameter
D.
The distance of the crusher roll 3 above the anvil plate 6 determines
the throat height H for the mineral matter to be comminuted and
hence the maximum size of the pieces to be handled.
The breaker shaft 4 forms the axis for a pair of rotating circular
disks 7 constituting flywheels and keyed to hubs 7a which in turn
are keyed to the shaft 4 the hubs 7a forming part of the crusher
roll 3. The disks 7 are disposed at the outer ends of the crusher
roll within the housing and thus flank the array of hammers 5. The
inner faces 7b of the disk 7 define the width W of the channel through
which the mineral material is displaced.
Between the arms 2a and 2b of the bifurcated support 2 and the
respective spinning disks 7 the side walls 8 of the housing 20
are formed with guide slots 10 through which the shaft 4 passes
and which allows the vertical adjustment of the axis A of the roll
with respect to the anvil 6.
The disks 7 have a diameter substantially larger than the lengths
of the slots 10 so that they completely overlie these slots in all
positions of the crusher roll and prevent escape of the comminuted
material through these slots. In the embodiment illustrated and
in the preferred construction, the diameters of the disks 7 correspond
to the impact circle diameter D.
The hammers 5 are constituted as disk segments 11 with hammerheads
12 and are disposed in pairs with the segments of each pair offset
through 180.degree. about the axis A.
The bifurcated support 2 is provided at the free ends of the arms
2a , 2b with fluid-responsive piston-cylinder arrangements 14 which
may be vertical adjustments of the roll 3. Each of the arrangements
14 is connected to a height adjustment device 15 (see FIG. 1). For
an especially compact construction of the system, a pedestal 16a
is provided to carry a flat transmission 16 running from the motor
unit 18 and operating the drive stub 17 of shaft 4 via V-belts and
pulleys not shown. |