U.S. patent application number 12/723301 was filed with the patent office on 2011-09-15 for mold for forming compacted mass having a grooved surface.
This patent application is currently assigned to BEPEX INTERNATIONAL, LLC. Invention is credited to Joseph P. McHale, Donald K. Swatling.
Application Number | 20110219678 12/723301 |
Document ID | / |
Family ID | 44558574 |
Filed Date | 2011-09-15 |
United States Patent
Application |
20110219678 |
Kind Code |
A1 |
McHale; Joseph P. ; et
al. |
September 15, 2011 |
MOLD FOR FORMING COMPACTED MASS HAVING A GROOVED SURFACE
Abstract
A mold for use in a rotary compactor in order to form compacted
mass products (e.g., briquets) from a compactable material, the
mold having at least one roll pocket that is provided with a
surface configuration adapted to impart corresponding grooves to
the respective mass surface, and in turn, to provide a physical
barrier to the flow of the compactable material adapted to impart
an optimal balance between releasability and wear resistance as
compared to a pocket previously known in the art.
Inventors: |
McHale; Joseph P.; (Coon
Rapids, MN) ; Swatling; Donald K.; (Oakland,
CA) |
Assignee: |
BEPEX INTERNATIONAL, LLC
Minneapolis
MN
|
Family ID: |
44558574 |
Appl. No.: |
12/723301 |
Filed: |
March 12, 2010 |
Current U.S.
Class: |
44/550 ;
425/237 |
Current CPC
Class: |
C10L 5/361 20130101;
B30B 11/165 20130101 |
Class at
Publication: |
44/550 ;
425/237 |
International
Class: |
C10L 5/00 20060101
C10L005/00; C10L 5/08 20060101 C10L005/08 |
Claims
1. A mold for use in a rotary compactor, the mold comprising a
plurality of roll pockets adapted to form a briquet from a
compactable material, the pockets comprising: a) a first pocket
adapted to impart a substantially convex upper surface to the
briquet, and b) a second pocket adapted to impart a substantially
convex opposite (lower) surface to the briquet; c) at least one of
the first and second pockets comprising a surface configuration
adapted to impart corresponding grooves or dimples to the
respective briquet surface; d) the surface configuration providing
a physical barrier to the flow of the compactable material adapted
to impart an optimal balance between releasability and wear
resistance as compared to a pocket previously known in the art.
2. A mold according to claim 1, wherein the mold provides an
improved combination of both service life and economy, as compared
to roll pockets previously known.
3. A mold according to claim 1, wherein at least one roll pocket
comprises one or more reliefs, positioned in a manner that is
sufficiently offset from the direction of material flow.
4. A mold according to claim 3, wherein the relief is sufficient to
provide an improved damming effect, thereby impeding the flow of
material, in a manner sufficient to lessen abrasion of the pocket
surface, and thereby improve the useful working life of the
pocket.
5. A mold according to claim 4, wherein the pocket comprises a
plurality of such relief portions, selected from the group
consisting of offset parallel lines, or cross-hatched lines.
6. A roll pocket adapted for use in the mold of claim 1.
7. A briquet formed using the mold of claim 1.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the formation of compacted mass
products, such as briquets formed from charcoal and other solid
(e.g., particulate) biomass materials. More particularly, the
present invention relates to the formation of generally
pillow-shaped briquets by means of roller or rotary molding.
BACKGROUND OF THE INVENTION
[0002] Compacted masses can be formed from a variety of materials,
and into a corresponding variety of forms (e.g., briquettes or
compacted sheets). Such sheets, for instance, can be subsequently
gound and screened to achieve desired particle sizes for a
particular end use or need (e.g., as fertilizer or cat litter).
[0003] Briquettes formed of charcoal and other materials (e.g.,
biomass) are often configured in a generally pillow-shape. This
configuration provides for both reasonable ease of manufacturing by
the supplier, and handling by the consumer. See, for instance, U.S.
Pat. No. 5,049,333 (Briquet Forming Apparatus and Method), as well
as U.S. patent application Ser. No. US 2006/0064926 (Charcoal
Briquet Having a Grooved Surface), the disclosures of both of which
are incorporated herein by reference. The '926 application, in
turn, describes a briquet having a generally pillow-shaped briquet
having a generally convex upper surface, a generally convex lower
surface, and a periphery wherein at least one of the upper or lower
surfaces has located thereon enhanced surface textured features in
the form of at least one groove, channel, trench or the like. As
described therein, "when two or more grooves are present on one or
both surfaces, the grooves are preferably parallel to each other,
parallel to two opposing sides of the briquet, and perpendicular to
two other opposing sides of the briquet. The presence of one or
more grooves on or both surfaces increases the surface area to
volume ratio thereby enabling more of the briquet to be exposed to
oxygen."
[0004] Generally, the roll pockets for use in a rotary compactor
need to be replaced when their useful service life has been
expended, thereby adding to the corresponding cost of manufacturing
the corresponding material (e.g., briquettes). In turn, it would be
quite beneficial to be able to improve the service life of roll
pockets, particularly if it can be done without detrimental impact
on their overall use or other desireable properties relating to
either the pockets themselves, or the compacted masses thus
formed.
SUMMARY OF THE INVENTION
[0005] In one preferred embodiment, the present invention provides
a mold for use in a rotary compactor, the mold comprising a
plurality of roll pockets adapted to form a compacted mass (e.g.,
briquet) from a compactable material. In a preferred embodiment,
the mold provides a plurality (e.g., pair) of replaceable, opposing
roll pockets, adapted to form a compacted mass, the pockets
comprising: [0006] a) a first pocket adapted to impart a
substantially convex upper surface to the compacted mass, and
[0007] b) a second pocket adapted to impart a substantially convex
opposite (lower) surface to the compacted mass; [0008] c) at least
one of the first and second pockets comprising a surface
configuration adapted to impart corresponding grooves to the
respective compacted mass surface; [0009] d) the surface
configuration of at least one roll pocket providing a physical
barrier to the flow of the compactable material adapted to impart
an optimal balance between releasability and wear resistance as
compared to pockets previously known in the art.
[0010] In turn, a roll pocket of the present invention provides an
improved combination of both service life and economy, as compared
to roll pockets previously known.
[0011] In one preferred embodiment, for instance, at least one roll
pocket comprises one or more reliefs, positioned in a manner that
is sufficiently offset from the direction of material flow. The
relief(s), in turn, is sufficient to provide a damming effect,
thereby impeding the flow of material, in a manner sufficient to
lessen abrasion of the pocket surface by the material itself, and
thereby improve the useful working life of the pocket. In addition
to its damming effect, however, the relief is also sufficient
(e.g., in terms of its size, dimensions, and orientation) to permit
suitable release of the compacted material, once formed.
[0012] In a particularly preferred embodiment, the pocket comprises
a plurality of such relief portions, e.g., in the form of parallel
lines, or cross-hatched lines (e.g., as in the general form of an
"X", a "K", or an inverted chevron), wherein at least one such line
is offset from the path of material flow.
[0013] In a particularly preferred embodiment, a pair of opposing
roll pockets is provided (also referred to as a pocketed roll),
adapted to form a briquet having grooves on both major convex
surfaces, the pockets having improved wear resistance, sufficient
to permit significantly more feed material to be formed, as
compared to roll pockets previously used. For instance, the
improved wear resistance preferably corresponds to between about 10
and about 50% longer life before replacement of a roll pocket, and
preferably 25 to 35% longer life, as compared to a pocket without
such surface configuration. In a particularly preferred embodiment,
the mold comprises a pair of opposing roll pockets, each of which
provide at about 10% or more, and preferably about 15% or more
longer life for either or both pockets as previously known and
described (e.g., as described in U.S. patent application Ser. No.
US 2006/0064926 cited above).
[0014] Without intending to be bound by theory, it appears that the
surface configuration provided by a roll pocket of this invention
is sufficient to grab feed material, on the one hand, thereby
slowing or "damming" the flow of material through the pocket (and
in turn, lessening abrasive wear), while at the same time,
facilitating release of the formed briquette.
[0015] In turn, those skilled in the art, given the present
description, will appreciate the manner in which the geometric
configuration of either or both pockets, and corresponding surface
configurations, can be determined, based on such considerations as
the particle size, moisture content, compaction pressure, and
release characteristics of the feed material itself.
[0016] Those skilled in the art will further appreciate, given the
present description, the manner in which various factors can be
determined in order to achieve the goals and improvement described
herein. These include, for instance, the orientation of reliefs
(e.g., offset parallel lines, cross-hatched lines, etc.), the
dimensions of any particular relief (e.g., height, length, radii),
the operational conditions (e.g., material velocity, pressure), and
the material itself (e.g., particle size, moisture, density,
abrasiveness).
[0017] In turn, the mold of the present invention can be used to
compact any suitable material, including for instance, powdered or
granular charcoal, biomass, steel mill byproducts, fertilizer, and
the like.
[0018] In an other aspect, the present invention provides a
compacted mass (e.g., briquet) formed using a pocket roll and
corresponding method of this invention. Such a briquet will
generally have a generally pillow-shaped briquet having a generally
convex upper surface, a generally convex lower surface, and a
periphery wherein at least one of the upper or lower surfaces has
located thereon enhanced surface textured features in the form of
at least one groove, channel, trench or the like, generally
corresponding to the surface configuration on the pocket rolls used
to form the compacted mass.
[0019] In yet another aspect, the invention provides replacement
parts, in the form of roll pockets, individually or in pairs, for
use with a rotary mold in accordance with this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The following drawings are illustrative of particular
embodiments of the present invention and therefore do not limit the
scope of the invention. The drawings are not to scale (unless so
stated) and are intended for use in conjunction with the
explanations in the following detailed description. Embodiments of
the present invention will hereinafter be described in conjunction
with the appended drawings, wherein like numerals denote like
elements.
[0021] FIG. 1 is a side view of a rotary compactor according to
some embodiments of the invention.
[0022] FIG. 2 is a schematic diagram illustrating engagement of
opposing roll presses according to some embodiments of the
invention.
[0023] FIG. 3 is a partial side cut-away and cross-sectional view
of a press roll according to some embodiments of the invention.
[0024] FIG. 4A-4C are various views of a prior art roll pocket
including parallel reliefs, having lengths substantially parallel
to the flow of material.
[0025] FIGS. 5A-5D are various views of a roll pocket including
parallel reliefs according to some embodiments of the
invention.
[0026] FIGS. 6 is a partial side cut-away and cross-sectional view
of a press roll according to some embodiments of the invention.
[0027] FIGS. 7A-7C are various views of a prior art roll pocket
including a K-shaped relief.
[0028] FIGS. 8A-8C are various views of a roll pocket including a
K-shaped relief according to some embodiments of the invention.
[0029] FIGS. 9A-9B are various views of a roll pocket including
corner relief portions according to some embodiments of the
invention.
[0030] FIGS. 10A-10B are various views of a roll pocket including
angled relief portions according to some embodiments of the
invention.
DETAILED DESCRIPTION
[0031] The following detailed description is exemplary in nature
and is not intended to limit the scope, applicability, or
configuration of the invention in any way. Rather, the following
description provides some practical illustrations for implementing
exemplary embodiments of the present invention. Examples of
constructions, materials, dimensions, and manufacturing processes
are provided for selected elements, and all other elements employ
that which is known to those of ordinary skill in the field of the
invention. Those skilled in the art will recognize that many of the
noted examples have a variety of suitable alternatives.
[0032] Briquetting can be performed using various approaches. Roll
type briquette machines apply pressures to particles by squeezing
them between two rolls rotating in opposite directions. In turn,
pockets (e.g., including or in the form of cavities or
indentations) can be cut into the surfaces of the rolls for use in
forming the briquettes.
[0033] Modern briquette machines usually have only one roll in a
fixed position in the frame. The other roll is moveable, but is
restrained by hydraulic cylinders. The rolls may be arranged
horizontally or side by side in the frame, or they may be arranged
vertically or one above the other as in rolling mills. The rolls
additionally may be located symmetrically between the bearings or
they may be mounted outside the bearings at the end of cantilevered
shafts. Each of these four arrangements has certain unique
properties. Other features of the machines as well can be varied to
satisfy special process conditions. Six characteristics in all
determine the behavior of roll type briquette machines.
[0034] Briquette machine rolls are classified according to their
construction as integral, solid or segmented. Integral rolls, as
the name implies, are made integral with the shafts. These rolls
usually have a band of stainless steel or some corrosion or
abrasion resistant material welded to their circumference or
working face. Since they have no joints or mating surfaces,
integral rolls are frequently used for briquetting food or
pharmaceutical products where cleanliness is of primary concern.
Integral rolls can easily be steam heated or water cooled. They are
not generally suitable for abrasive materials.
[0035] Solid rolls or tires are the most commonly used briquetting
rolls and consist of replaceable rings keyed or shrink fitted to
the shafts. The rolls are made from a variety of abrasion and
corrosion resistant materials. Unlike integral rolls, which require
some compromise in materials of construction, solid rolls and
shafts can each be made from the most suitable material.
[0036] Segmented rolls are made in a series of sections or segments
which are mechanically clamped to the shafts. The advantages of
segmented rolls are obvious to anyone who has ever changed
conventional rolls, so rolls of this type have been the subject of
continuing investigation since the beginning of the briquetting
industry. Segmented rolls are recommended for briquetting hot or
abrasive materials and are made from materials suitable for such
applications.
[0037] The mechanical construction of the rolls determines such
important characteristics as reliability, ease of maintenance and
cost of operation. The effect that the rolls will have upon
materials passing through them, however, depends on their geometry.
In most briquette machines, the moveable roll is pressed against a
fixed roll by hydraulic cylinders. Stops located between the
bearing blocks prevent the rolls from coming in contact with each
other. Material passing between the rolls attempts to spread them
apart. The hydraulic cylinders resist this effort until the force
exerted by the material exceeds that exerted by the cylinders. The
moveable roll is then displaced and in turn displaces the pistons
in the hydraulic cylinders until both efforts become equal. The oil
displaced by the pistons is stored under pressure in a gas filled
accumulator. It returns from there as needed to push the moveable
roll back against the stops.
[0038] The hydraulic system acts like a spring. The initial force
holding the rolls together can be adjusted by the pressure of the
oil in the cylinders. The incremental force necessary to displace
the moveable roll is also adjustable by the volume of the gas in
the accumulator. The success of the modern roll type briquette
machine is due in no small part to this ability of the hydraulic
system to match the slope of the force-displacement curve of the
moveable roll to the requirements of the briquetting process. When
roll type briquette machines were limited to compacting materials,
which were mixed with binders, the simple gravity type feeder was
usually adequate. Briquetting in this case is primarily a forming
or molding process and little change in the density of the product
occurs as it passes through the rolls. The pressure required for
such applications is low and the virtue of simplicity frequently
outweighs the advantages possible from more sophisticated
control.
[0039] Gravity type feeders consequently are still used for some
purposes. For dry or finely divided materials, screw or auger type
feeders are commonly used. These feeders in addition to controlling
the mass of material passing between the rolls, frequently have
important secondary effects. They may precompress the material
before it reaches the rolls. They may crush the particles to
achieve a more favorable size consistency. There is speculation
that the mobility of the particles in the feed screw allows the
crystal axes to align themselves more favorably so as to produce
better quality briquettes. Heating of the particles in the screw
feeder may also have a significant effect. Whatever the mechanisms
may be, briquettes of better quality frequently can be made by
using a screw feed.
[0040] FIG. 1 is a side view of a rotary compactor 100 (also
referred to herein as a "briquette machine") according to some
embodiments of the invention. The general design and construction
of rotary compactors is well known in the art, and for the sake of
clarity only a brief overview of the rotary compactor 100 is
provided herein. Those skilled in the art will appreciate that
rotary compactors are complex machines including numerous
components not included in the discussion herein. The roll
compactor 100 generally includes opposing roll assemblies 104, 106
that are mounted and engaged within the compactor 100 in a manner
that facilitates the briquetting functionality of the compactor
100. The compactor 100 further includes a feeder assembly 102
positioned above the roll assemblies 104, 106 that receives
briquette material and feeds the material to the roll assemblies.
The roll assemblies 104, 106 comprise a number of components
familiar to those skilled in the art, including press rolls or
molds that include a number of roll pockets configured to receive
the material from the feeder assembly 102 and form it into
briquettes.
[0041] FIG. 2 illustrates at least a portion of this process. FIG.
2 is a schematic diagram illustrating engagement of opposing roll
presses 200, 202 according to some embodiments of the invention.
Each roll press 200, 202 includes a number of roll pockets 204
(shown in cross-section). As the first press roll 200 rotates in
direction 208 (clockwise in FIG. 2) and the second press roll 202
rotates in direction 210 (counterclockwise in FIG. 2), briquette
material is introduced to the rolls in the direction of material
flow 206. The roll pockets 204 in the opposing press rolls come
together and form a mold that receives the briquette material. The
press rolls and pockets then press together to compact the material
into a briquette (or other compactable mass) having a desired
shape.
[0042] As conventional press rolls rotate together and compact the
briquette material, there is a tendency for the briquette material
to expand and push out of the roll pockets in direction 212 due to
the pressure and continuous rotation of the press rolls. This is
sometimes referred to as material "washout." The washed out
material often abrades the press roll pockets, leading to undesired
wear and poor performance along the trailing edge of the roll
pocket, among other places. Embodiments of the invention provide
one or more of the roll pockets with an improved surface
configuration that provides an improved damming effect, thereby
impeding the flow of washed out material in direction 212, in a
manner sufficient to lessen abrasion of the pocket surface. This
improves the useful working life of the pocket.
[0043] FIG. 3 is a partial cut-away and cross-sectional view
showing a portion of a press roll 300 according to some embodiments
of the invention. FIG. 3 is a view of the press roll 300 from an
orientation perpendicular to the axis of rotation 306, and shows a
portion of the outer surface or "face" 302 of the press roll 300.
The press roll 300 includes a number of roll pockets 304 arranged
on the face 302 of the press roll 300. While FIG. 3 shows two rows
of roll pockets 304 extending across the face 302 of the roll 300,
it should be appreciated that in some embodiments the roll pockets
cover substantially the entire face 302 of the press roll in the
form of consecutive rows.
[0044] As shown near the top of FIG. 3 in cross-section, the
pockets 304 are formed as depressions or hollowed-out portions in
the face 302 of the press roll 300. In some embodiments the pockets
304 may be formed integrally within the surface of the press roll.
In some embodiments the pockets 304 may be formed in mold segments
that can be fixed to the surface of the press roll. Returning to
FIG. 3, the roll pockets 304 have a surface configuration including
two substantially parallel reliefs 314 that are angled with respect
to the direction of compactable material flow 308 (and also with
respect to the direction of material washout 212 shown in FIG. 2).
The rotation of the press roll 300 around the axis of rotation 306
defines a direction of rotation similar to the direction 308 of
compactable material flow. The rotation also defines leading edges
310 and trailing edges 312 of each roll pocket 304.
[0045] FIG. 4A-4C are various views of a prior art roll pocket 400
including a pair of parallel reliefs 412 oriented substantially
parallel to a direction of flow 422 of the compactable material.
FIGS. 4A-4C show the bottom, contoured surface 404 of the roll
pocket 400 as it is formed in the press roll 402 (shown in dotted
lines) with the pocket opening 406 positioned at the face of the
roll. FIG. 4A shows a top view of the roll pocket 400, illustrating
the two reliefs 412. The reliefs 412 are formed in the roll pocket
400 with a fillet 414 providing a smooth transition between the
surface of the pocket 404 and portions of the reliefs 412. The roll
pocket 400 has a leading edge 408 and a trailing edge 410
determined by the direction of rotation of the press roll. FIG. 4B
illustrates an end view of the roll pocket 400 taken along line BB
shown in FIG. 4A, showing a profile view of the reliefs 412.
Various dimensions of the roll pocket surface configuration are
also denoted, including the pocket depth 416, the relief height 418
as measured from the maximum pocket depth, and the relief depth 420
defined from the surface of the press roll.
[0046] FIGS. 5A-5D are various views of an improved roll pocket 500
according to some embodiments of the invention. The roll pocket 500
has a surface configuration including substantially parallel
reliefs 512 oriented at an angle 526 with respect to a longitudinal
axis 524 of the reliefs and the direction of material flow and
press roll rotation 522. FIG. 5A shows a top plan view of the
pocket 500. As shown in FIG. 5B, which is a side view of FIG. 5A
taken along line BB, the roll pocket 500 is formed as a depression
in the press roll 502, having a contoured bottom surface 504 and an
opening 506 in the face of the press roll 502. As shown in FIGS. 5A
and 5C, the reliefs 512 are formed as elongated, raised ridges
having a curved surface. Fillets 514 provide a stepped transition
between the reliefs and the surrounding surface 504 of the roll
pocket 500 that improves the releasability characteristics of the
pocket.
[0047] Returning briefly to FIG. 2, when compactable material is
introduced to the mold formed by the opposing roll pockets 204 and
the roll pockets compress together as the press rolls 200, 202
rotate, the compactable material tends to be pushed out of the
pockets in a direction 212 opposite the direction of rotation 208,
210. Accordingly, the material is pushed from the leading edge to
the trailing edge of the pocket, and in some cases out of the
pocket proximate the trailing edge. Returning to FIG. 5A, according
to some embodiments the surface configuration (e.g., reliefs 512)
of the roll pocket 500 provides a physical barrier to this backflow
or washout of the compactable material as it is pushed from the
leading edge 508 of the pocket to the trailing edge 510 of the
pocket 500. The physical barrier reduces the amount of material
being washed out of the pocket, thus reducing wear on the pocket
and extending the useful life of the roll pocket 500.
[0048] Accordingly, one or more reliefs can effectively trap some
of the compactable material as it is pushed back out of the pocket,
reducing washout and wear on the pocket. In the example shown in
FIGS. 5A-5D, the two reliefs 512 provide trapping edges 528 that
act as physical barriers to the flow of the compactable material
toward the trailing edge 510 of the pocket. The reliefs 512 thus
create "trap zones" 530 between the leading edge 508 of the pocket
and the trapping edges 528. Turning to FIGS. 4A-4C, the example of
the prior art roll pocket 400 does not provide a surface
configuration that forms a barrier to movement of the compactable
material toward the trailing edge 410 of the pocket 400 (opposite
the direction of material flow 422). Instead, the roll pocket 400
includes reliefs 412 that are substantially parallel to the
direction 422 of material flow, allowing material to move more
freely toward the trailing edge 410 of the pocket.
[0049] Returning to FIGS. 5A-5D, in some embodiments of the
invention, the dimensions of the various contours and reliefs on
the surface 504 of the roll pocket 500 can also provide an improved
capability to trap or "dam" compactable material within the roll
pocket. For example, in some embodiments the reliefs 512 of the
roll pocket 500 have an increased height 518 with respect to the
pocket depth 516 than in previous roll pockets. The increased
height of the relief 512 presents a higher physical barrier to
material moving within the pocket, thus decreasing wear and
increasing the useful life of the pocket 500.
[0050] Accordingly, one or more aspects of the roll pocket 500
provide improved performance over the prior art roll pocket 400.
For example, it is believed that improvements in the surface
configuration of the improved roll pocket 500 can increase the
serviceable life of the roll pocket 500 by about 30% with respect
to the prior art roll pocket 400. Similarly, it is estimated that a
typical, improved roll pocket 500 can process about 30% more
compactable material than previous roll pockets before needing
replacement.
[0051] FIG. 6 is a partial cut-away and cross-sectional view
showing a portion of a press roll 600 according to some embodiments
of the invention. FIG. 6 is a view of the press roll 600 from an
orientation perpendicular to the axis of rotation 606, and shows a
portion of the outer surface or "face" 602 of the press roll 600.
The press roll 600 includes a number of roll pockets 604 arranged
on the face 602 of the press roll 600. While FIG. 6 shows two rows
of roll pockets 604 extending across the face 602 of the roll 600,
it should be appreciated that in some embodiments the roll pockets
cover substantially the entire face 602 of the press roll in the
form of consecutive rows.
[0052] As shown near the top of FIG. 6 in cross-section, the
pockets 604 are formed as depressions or hollowed-out portions in
the face 602 of the press roll 600. In some embodiments the pockets
604 may be formed integrally within the surface of the press roll.
In some embodiments the pockets 604 may be formed in mold segments
that can be fixed to the surface of the press roll. Returning to
FIG. 6, the roll pockets 604 have a surface configuration including
a K-shaped relief 614 having relief portions angled with respect to
the direction of compactable material flow 608 (and also with
respect to the direction of material washout 212 shown in FIG. 2).
The rotation of the press roll 600 around the axis of rotation 606
defines a direction of rotation similar to the direction 608 of
compactable material flow. The rotation also defines leading edges
610 and trailing edges 612 of each roll pocket 604.
[0053] FIG. 7A-7C are various views of a prior art roll pocket 700
including a K-shaped relief 712. FIGS. 7A-7C show the bottom,
contoured surface 704 of the roll pocket 700 as it is formed in the
press roll 702 (shown in dotted lines) with the pocket opening 706
positioned at the face of the roll. FIG. 4A shows a top view of the
roll pocket 700, illustrating the K-shaped relief 712. The relief
712 is formed in the roll pocket 700 with a fillet 714 providing a
smooth transition between the surface of the pocket 704 and
portions of the relief 712. The roll pocket 700 has a leading edge
708 and a trailing edge 710 determined by the direction of rotation
of the press roll. FIG. 7B illustrates an end view of the roll
pocket 700 taken along line BB shown in FIG. 7A, showing a profile
view of the relief 712. Various dimensions of the roll pocket
surface configuration are also denoted, including the pocket depth
716, the relief height 718 as measured from the maximum pocket
depth, and the relief depth 720 defined from the surface of the
press roll.
[0054] FIGS. 8A-8D are various views of an improved roll pocket 800
according to some embodiments of the invention. The roll pocket 800
has a surface configuration including a K-shaped relief 812 having
portions of the relief oriented at an angle with respect to the
direction of material flow and press roll rotation 822. FIG. 8A
shows a top plan view of the pocket 800. As shown in FIG. 8B, which
is a side view of FIG. 8A taken along line BB, the roll pocket 800
is formed as a depression in the press roll 802, having a contoured
bottom surface 804 and an opening 806 in the face of the press roll
802. As shown in FIGS. 8A and 8C, the relief 812 is formed as a
group of connected, elongated, raised ridges having curved
surfaces. Fillets 814 provide a stepped transition between the
relief and the surrounding surface 804 of the roll pocket 800 that
improves the releasability characteristics of the pocket.
[0055] According to some embodiments the surface configuration
(e.g., relief 812) of the roll pocket 800 provides a physical
barrier to the backflow or washout of the compactable material as
it is pushed from the leading edge 808 of the pocket to the
trailing edge 810 of the pocket 800. The physical barrier reduces
the amount of material being washed out of the pocket, thus
reducing wear on the pocket and extending the useful life of the
roll pocket 800.
[0056] Accordingly, the K-shaped relief (or one or more portions of
the relief) can effectively trap some of the compactable material
as it is pushed back out of the pocket, reducing washout and wear
on the pocket. In the example shown in FIGS. 8A-8D, the two angled
"legs" of the relief 812 provide trapping edges 828 that act as
physical barriers to the flow of the compactable material toward
the trailing edge 810 of the pocket. The relief 812 thus creates
"trap zones" 830 between the leading edge 808 of the pocket and the
trapping edges 828.
[0057] In some embodiments of the invention, the dimensions of the
various contours and reliefs on the surface 804 of the roll pocket
800 can also provide an improved capability to trap or "dam"
compactable material within the roll pocket. For example, in some
embodiments the relief 812 of the roll pocket 800 has an increased
height 818 with respect to the pocket depth 816 than in previous
roll pockets. The increased height of the relief 812 presents a
higher physical barrier to material moving within the pocket, thus
decreasing wear and increasing the useful life of the pocket 800.
With respect to FIG. 7B, for example, the prior art roll pocket 700
may have a relief height 718 of about 0.117 inches above the bottom
of the pocket, while the improved embodiment shown in FIG. 8B can
include a relief height 818 of about 0.202 inches. When compared
with pocket depths of 0.455 inches and 0.432 inches for the prior
art pocket 700 and the improved pocket 800, respectively, the
improved surface configuration of the pocket 800 provides a relief
height 818 that is about 47% of the pocket depth 816, while the
prior art pocket 700 only provides a relief height 718 of about 26%
of the pocket depth 716. The substantial increase in relief height
in proportion to pocket depth can provide improved trapping or
damming characteristics.
[0058] Accordingly, one or more aspects of the roll pocket 800
provide improved performance over the prior art roll pocket 700.
For example, it is believed that improvements in the surface
configuration of the improved roll pocket 800 can increase the
serviceable life of the roll pocket 800 by about 15% with respect
to the prior art roll pocket 700. Similarly, it is estimated that a
typical, improved roll pocket 800 can process about 15% more
compactable material than the previous roll pocket 700 before
needing replacement.
[0059] FIGS. 9A-9B are various views of a roll pocket including a
plurality of reliefs according to some embodiments of the
invention. The roll pocket 900 has a surface configuration
including raised corner reliefs 912 having portions oriented at an
angle with respect to the direction of material flow and press roll
rotation 922. FIG. 9A shows a top plan view of the pocket 900. As
shown in FIG. 9B, which is a front perspective view of FIG. 9A, the
roll pocket 900 is formed as a depression in the press roll 902,
having a contoured bottom surface 904 and an opening 906 in the
face of the press roll 902. As shown in FIGS. 9A and 9B, the
reliefs 912 are formed as a group of raised corner portions having
curved surfaces configured to form a raised cross or t shape in a
compactable mass. Fillets provide a stepped transition between the
reliefs and the surrounding surface 904 of the roll pocket 900 that
improves the releasability characteristics of the pocket.
[0060] According to some embodiments the surface configuration
(e.g., one or more of the reliefs 912) of the roll pocket 900
provides a physical barrier to the backflow or washout of the
compactable material as it is pushed from the leading edge 908 of
the pocket to the trailing edge 910 of the pocket 900. The physical
barrier reduces the amount of material being washed out of the
pocket, thus reducing wear on the pocket and extending the useful
life of the roll pocket 900.
[0061] Accordingly, one or more of the corner relief portions can
effectively trap some of the compactable material as it is pushed
back out of the pocket, reducing washout and wear on the pocket. In
the example shown in FIGS. 9A and 9B, the two upper corner reliefs
912 near the trailing edge 910 of the pocket provide trapping edges
928 that act as physical barriers to the flow of the compactable
material toward the trailing edge 910 of the pocket. The reliefs
912 thus creates "trap zones" 930 between the leading edge 908 of
the pocket and the trapping edges 928.
[0062] While FIGS. 9A and 9B show a surface configuration adapted
to form a raised cross in the compactable mass, a corresponding
inverted configuration is also possible in some embodiments. For
example, the pocket 900 could include a single cross shaped relief
that rises above the pocket surface 904 that is adapted to form a
raised cross shape with depressed dimples in the compressed
mass.
[0063] FIGS. 10A-10B are various views of a roll pocket including a
plurality of reliefs according to some embodiments of the
invention. The roll pocket 1000 has a surface configuration
including raised angled reliefs 1012 having portions oriented at an
angle with respect to the direction of material flow and press roll
rotation 1022. FIG. 10A shows a top plan view of the pocket 1000.
As shown in FIG. 10B, which is a front perspective view of FIG.
10A, the roll pocket 1000 is formed as a depression in the press
roll 1002, having a contoured bottom surface 1004 and an opening
1006 in the face of the press roll 1002. As shown in FIGS. 10A and
10B, the reliefs 1012 are formed as a group of raised angled
portions having curved surfaces configured to form a raised X shape
in a compactable mass. Fillets provide a stepped transition between
the reliefs and the surrounding surface 1004 of the roll pocket
1000 that improves the releasability characteristics of the
pocket.
[0064] According to some embodiments the surface configuration
(e.g., one or more of the reliefs 1012) of the roll pocket 1000
provides a physical barrier to the backflow or washout of the
compactable material as it is pushed from the leading edge 1008 of
the pocket to the trailing edge 1010 of the pocket 1000. The
physical barrier reduces the amount of material being washed out of
the pocket, thus reducing wear on the pocket and extending the
useful life of the roll pocket 1000.
[0065] Accordingly, one or more of the raised relief portions 912
can effectively trap some of the compactable material as it is
pushed back out of the pocket, reducing washout and wear on the
pocket. In the example shown in FIGS. 10A and 10B, the three upper
reliefs 1012 provide trapping edges 1028 that act as physical
barriers to the flow of the compactable material toward the
trailing edge 1010 of the pocket. The reliefs 1012 thus creates
"trap zones" 1030 between the leading edge 1008 of the pocket and
the trapping edges 1028.
[0066] While FIGS. 10A and 10B show a surface configuration adapted
to form a raised X shape in the compactable mass, a corresponding
inverted configuration is also possible in some embodiments. For
example, the pocket 1000 could include a single X-shaped relief
that rises above the pocket surface 1004 that is adapted to form a
raised X-shape with depressed dimples in the compressed mass.
[0067] According to some embodiments, the surface configuration of
a particular roll pocket may include one or more reliefs oriented
at a variety of angles with respect to the directions of material
flow/washout. For example, in some cases the surface configuration
may include a single, horizontal relief (or groove made from e.g.,
two horizontal reliefs) oriented substantially perpendicularly to
the direction of material flow. In some embodiments different
angular configurations such as an inverted V- or chevron-shaped
relief can be incorporated into the surface of the roll pocket.
Those skilled in the art will appreciate that a variety of surface
configurations are possible that have properties similar to those
of the described embodiments for providing an improved damming
effect on the flow of material out of a roll pocket.
[0068] Thus, embodiments of the invention are disclosed. Although
the present invention has been described in considerable detail
with reference to certain disclosed embodiments, the disclosed
embodiments are presented for purposes of illustration and not
limitation and other embodiments of the invention are possible. One
skilled in the art will appreciate that various changes,
adaptations, and modifications may be made without departing from
the spirit of the invention and the scope of the appended
claims.
* * * * *