Abstrict A roller mill such as a roll press or roll jaw crusher with crushing
rollers and end face plates for lateral limitation of the nip mounted
with pivotal links on the side walls of a product delivery chute
and triangularly spaced support springs for the face plates urging
them toward the nip with wear-resistant coatings on the inner surface
of the face plates with the face plates having a lower removable
extension.
Claims I claim as my invention:
1. A roller mill for receiving stock between rolls, comprising
in combination:
a pair of rotatably supported rolls adapted to be driven in opposite
directions with their upper surfaces moving toward each other for
receiving stock in the nip therebetween in a pressing operation;
a vertical chute extending downwardly toward the nip and positioned
for directing stock downwardly into the nip;
rigid supporting arms extending downwardly from sides of the vertical
chute;
face plates having vertical planar surfaces at ends of the nip
for defining said ends and confining material drawn into the nip
from the chute;
a pivotal mount for each of said plates for supporting the plates
on the chute;
a wear resistant lining on an inner surface of each of the face
plates;
a lower extension plate mounted at each lower end of the face plates
and facing the center of the nip;
means for adjusting the location of the lower end of each of the
face plates and for removably mounting the lower extension plates
on the face plates; and
coil compression springs for each face plate between said rigid
supporting arms and each face plate to separately resiliently urge
the face plates toward the nip, said springs being triangularly
arranged for each face plate with a lower spring facing the nip
and two upper springs being spaced apart.
2. In a roller mill for receiving stock between rolls constructed
in accordance with claim 1:
wherein said wear-resistant lining is graduated in wear-resistant
capabilities increasing in wear-resistance in a downward direction
toward the nip.
3. A roller mill for receiving stock between rolls constructed
in accordance with claim 1:
wherein each pivotal mount includes spaced links pivotally mounted
at their upper ends on the chute and at their lower ends on the
face plates.
Description BACKGROUND OF THE INVENTION
The invention relates to improvements in roller mills such as a
roll press or roll jaw crusher having face plates positioned at
the lateral ends of the nip.
In roller mills heretofore known, such as roller briquette presses
and roll jaw crushers, face plates have been located rigidly supported
on the product delivery chute with their surfaces facing the ends
of the nip. In these structures, the rigid connection of the face
plate resulted in a rigid positioning of the plates relative to
the nip and jammings between the roller and face plate occurred
during operation of the roller mill. This was particularly true
when with variation in loads, the rollers would tend to shift positions
so that possibly one roller assumed an oblique position relative
to the other roller. Such jammings resulted in a necessary operational
shut-down of the roller mill and loss of production during such
shut-down periods. The face plates, rigidly arranged at the ends
of the rolls, were subject to high wear and required frequent replacement
with the necessary involved expense of shut-down time and cost of
material, servicing and parts.
It is accordingly an object of the present invention to provide
a roller mill wherein the face plate construction enables disruption-free
continuous operation for long periods of time and eliminates problems
heretofore present such that of jamming of material between the
roller and the face plates and such as that of rapid and excessive
wear of the face plates.
A further object of the invention is to provide an improved roller
mill construction having uniquely related face plates which provide
for a better product in that they remain effective in their operation
throughout their operating life, which operating life is longer
than heretofore possible with structures which have been available.
FEATURES OF THE INVENTION
The foregoing objectives are achieved and the problems are solved
in that face plates are arranged in an elastically resilient manner
at the ends of the nip between the rollers. An arrangement is provided
wherein the face plates are supported on the side walls of the product
delivery chute permitting yieldable movement in an axial direction
relative to the rollers. In this manner, the rollers can move in
adjustment of the nip and can even assume angular positions relative
to one another when variances in grinding load occur or when noncrushable
materials pass between the rollers. When instances occur such as
that the rollers must shift, the face plates will automatically
adapt to the change in position of the rollers until the load between
the rollers or the materials which have caused the rollers to shift
passes through and then the face plates automatically resume their
normal effective limiting position with their inner surfaces parallel
to the ends of the roll retaining the materials in the nip. The
arrangement of the face plates not only prevents jammings between
the rollers at the face plates and not only automatically resume
normal effective operating position with change in position of the
rollers, but the plates need to be replaced considerably less frequently
in comparison to arrangements heretofore available.
German Patent No. 34 07 534 discloses a roller mill for pressure
comminution of brittle materials wherein face plates are provided
that can be adjusted toward one another or away from one another
and are arranged for lateral limitation of the nip. This structural
arrangement, however, is only intended to make it possible to adapt
the face plates to the readjustment or changing of the roller mill
and to accommodate different grinding stock and to permit adjustments
with change in throughput performance of the roller mill due to
change in conditions.
In accordance with the principles of the invention, the face plates
are detachably connected or supported to the side walls of the product
delivery shaft. This permits the face plates to be replaced as needed
in a simple and cost-saving manner.
In order to significantly increase the useful life of the face
plates, a further improvement of the present concept provides that
the face plates are equipped with a highly wear-resistant material,
particularly in the lower portion, and the wear-resistant material
can be graduated in thickness or wear-resistant capability in accordance
with the wear which experience shows occurs as the product enters
the nip. Also, the plates are arranged in multiple parts so that
the lower part which wears most quickly can be separately changed
and serviced.
Other objects, advantages and features of the invention will become
more apparent with the teaching of the principles thereof in connection
with the disclosure of the preferred embodiment in the specification,
claims and drawings, in which:
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of a roller press shown with
parts removed and constructed and operating embodying the principles
of the present invention; and
FIG. 2 is an end elevational view of the structure of FIG. 1.
DESCRIPTION
As illustrated in FIGS. 1 and 2 the roller mill shown includes
oppositely driven rollers 1 and 2 rotatably supported in suitable
bearing in a machine housing. The rollers define between them a
nip 3 arranged so that meal to be treated passes downwardly into
the nip to be crushed and discharged in a downward direction, with
the rolls rotating in the direction indicated by the arrowed lines
on the ends of the rolls in FIG. 2.
At the ends of the nip 3 are face plates 4 and 5 which limit the
nip and hold the material being ground and crushed within the nip.
The inner surfaces of the face plates 5 are flat and essentially
co-planar with the end faces of the rollers 1 and 2 slidably engaging
the ends of the rollers to prevent the escape of meal laterally
out from the axial ends of the nip.
Material is delivered to the nip from a product delivery shaft
or chute 8 having side walls 6 and 7.
The face plates 4 and 5 are supported on and mounted on the side
walls by a unique support arrangement including pivotal links 9
and 10. The pivotal links are pivotally supported on their upper
ends at 11 and are connected to the face plates pivotally at their
lower ends 12. As a result of this articulated support of the face
plates on the side walls 6 and 7 of the chute, the face plates are
yieldably supported by this articulated connection being free to
move in and out and tilt about a horizontal axis transverse of the
axis of the rollers. When an oblique positioning of a roller occurs
during operation of the roller mill or when materials penetrate
between the rollers and the face plates, this articulated support
forms a releasable connection for the face plates on the product
chute. This arrangement also enables them to be replaced as needed
and reserviced quickly with minimum outlay for down-time and expense.
In accordance with the principles of the invention, the face plates
4 and 5 are elastically and yieldably supported against the ends
of the rollers, against the end of the nip, such as by spaced springs
17 and 18. These springs are supported on rigid brackets 13 and
14 supported on the side walls 6 and 7 of the supply chute. Because
of this elastically resilient support of the face plates 4 and 5
by the springs which push them inwardly in an axial direction, the
face plates can yield with shifting movement of the rollers such
as when one roller takes an oblique position relative to the other
or with given overloads and this movement is permitted to avoid
damage or destruction of the plates or of the rollers.
The wear of the face plates 4 and 5 is also considerably reduced
in this manner and thus the useful life of the face plate is correspondingly
increased.
Since the face plates 4 and 5 particularly in their middle and
lower regions, are exposed to particularly high wear during operation
of the roller mill, each face plate is constructed to be in multiple
parts. In particular, the face plates have a lower extension part
19 and 20. These lower parts are mounted on the upper parts of the
face plates by bolts 21 and 22. These bolts are removable for replacement
of the lower parts and in one contemplated form, the bolts extend
through elongate holes so that the lower inner surfaces of the face
plates can be aligned to be co-planar with the inner surfaces of
the upper parts of the face plates. This provides the advantage
that with expected wear of the face plates in the lower region,
only the lower parts 19 and 20 need be replaced and not the overall
face plates.
Further, the bolts 21 and 22 permit adjustment of the lower parts
of the face plates with wear to bring their inner surfaces into
the proper position with wear. The adjustment can be continued until
wear occurs to the extent where a planar surface no longer remains
and lateral sealing of the nip 3 is inadequate. Then the plates
can be discarded and be replaced by new extension face plates. This
not only enables a further significant increase in useful life of
the face plates, but produces a considerable saving of material
and costs.
It is further contemplated that the face plates 4 and 5 can be
coated with a wear-resistant material on their inner surface and
that their extensions can also be coated. In one form, the wear-resistance
of the coating or the thickness of the coating can be increased
in a downward direction so that the wear-resistance increases downwardly
as a function of the expected wear. The coating can be arranged
so that a highly wear-resistant layer can be coated in the middle
and lower regions.
The support springs which urge the face plates inwardly are shown
at 17 and 18 and are triangularly arranged with a lower spring directly
opposite the nip in the center thereof and laterally spaced upper
springs adjacent the links 9. The springs are supported on the rigid
brackets 13 and 14 by spring connecting bolts 15 and 16. This arrangement
of the springs has been found to be advantageous and balances the
expected lateral pressures of the meal in the nip.
Thus, it will be seen that I have provided an improved mill arrangement
which meets the objectives and advantages above set forth and provides
a structure which not only reduces the costs in terms of accommodating
wear but provides for more satisfactory operation thereby improving
the nature of the product produced by the mill. |