U.S. patent number 3,897,183 [Application Number 05/240,085] was granted by the patent office on 1975-07-29 for briquette molding apparatus and breaker.
This patent grant is currently assigned to United States Steel Corporation. Invention is credited to Gottfried Hofmann, Frank Kennedy.
United States Patent |
3,897,183 |
Hofmann , et al. |
July 29, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Briquette molding apparatus and breaker
Abstract
Loose material such as iron ore may be formed into a briquette
sheet and separated into their individual briquettes by applying
impact forces on opposite sides of the briquette sheet and to next
adjacent briquettes.
Inventors: |
Hofmann; Gottfried
(Lutzelfuh-Goldbach (BE), CH), Kennedy; Frank (Mount
Lebanon Twp., Allegheny County, PA) |
Assignee: |
United States Steel Corporation
(Pittsburgh, PA)
|
Family
ID: |
22905057 |
Appl.
No.: |
05/240,085 |
Filed: |
March 31, 1972 |
Current U.S.
Class: |
425/78; 225/103;
425/308; 425/335; 225/97; 425/237; 425/324.1; 425/363 |
Current CPC
Class: |
B30B
15/0005 (20130101); B30B 11/16 (20130101); Y10T
225/329 (20150401); Y10T 225/371 (20150401) |
Current International
Class: |
B30B
11/00 (20060101); B30B 15/00 (20060101); B30B
11/16 (20060101); B29c 003/02 () |
Field of
Search: |
;425/78,237,308,449,363,406,408,371,79,324R,335
;225/104,97,103 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spicer, Jr.; Robert L.
Attorney, Agent or Firm: Callaghan; John E.
Claims
We claim:
1. In a briquetting machine including roller presses that form
sheets of briquettes, the improvement which comprises:
at least two impacting devices, located adjacent to the sheet exit
of said machine and arranged opposite to each other along the
length of said exit,
each of said devices having one or more impact means,
each of said means being adapted to apply impact forces at the
plane of each sheet, and
movement control means to bring the impact means of the opposed
devices into parallel overlapping relationship with each other at
the plane of the sheet exit and spaced from each other a distance
corresponding to the distance between parallel briquette pockets in
the briquetting machine.
2. The machine of claim 1 wherein said impact devices include a
cylindrical support member axially aligned with the length of said
sheet exit and having mounted thereon a plurality of impact means
extending radially outwardly from said support.
3. The machine of claim 2 wherein said impact means are solid
members rigidly attached to said support.
4. The machine of claim 3 wherein the impact means are disposed in
rows, each row being staggered with respect to its peripherally
adjacent rows.
Description
BACKGROUND OF THE INVENTION
Agglomerating of loose materials into pillows or D-shaped lumps has
been done by means of roll presses. These presses have rollers with
pocketed surfaces to shape the material. Because of the high
pressures, it is necessary to have some clearance between the
rolls, but the briquettes are then formed with interconnected
ligaments or lands of material between the individual pillows. This
results in a briquette sheet which must be broken into its
individual members. Especially when compacting iron ore or reduced
iron ore, separation of the sheet with string breakers has been a
problem; this is described in U.S. Pat. No. 3,593,378 and U.S. Pat.
No. 3,300,815.
The briquettes from reduced iron ore are used in direct reduction
processes. Commonly, iron ore is heated to about 1500.degree. to
1900.degree.F and formed into briquettes under roll pressures of 50
to 350 tons. In some cases, the iron ore is treated in a fluidized
bed to remove about 75 percent of its oxygen, then it is briquetted
for use in direct reduction processes; this is described in more
detail in "The Making, Shaping and Treating of Steel", H. E.
McGannon, ed, 9th ed, 1971, United States Steel Corporation,
Pittsburgh, Pa., pp. 218-228, 403-421. In such processes, it is
particularly important that the briquettes have smooth, complete
shapes with a minimum of broken sizes and irregular jagged
edges.
OBJECTS OF THE INVENTION
This invention concerns briquetting of loose materials and has the
following objects.
A method and an apparatus for briquetting in which sheets of
briquettes are separated into individual members; to have such a
method in which a single step is sufficient to cause such
separation; to utilize such a method particularly with loose
materials that contain iron ore especially when such briquettes are
used in direct reduction of iron. These objects include briquetting
apparatus having improved means for separating sheets of briquettes
into individual members providing in the apparatus, such means that
will deliver impact forces to opposing sides of the briquette
sheets and at spaced apart positions on said sheet and which means
is self-cleaning and jam-free in operation.
SUMMARY OF INVENTION AND DRAWINGS
These and other objects are achieved by methods and apparatus that
provide for forming sheets of briquettes, then applying impact
forces to opposite sides of the sheet and then continuing the
application of forces across the thickness of the sheet. This
causes each briquette to simultaneously separate from its
neighbors.
FIG. 1 illustrates a briquetting apparatus according to this
invention.
FIG. 2 is a sectional view of the apparatus of FIG. 1.
FIG. 3 illustrates a briquette sheet as formed by the apparatus in
FIG. 1.
FIG. 4 is a view of this sheet showing the profile of
briquettes.
DESCRIPTION OF THE INVENTION
In the practice of the invention, loose material is formed into
sheets of briquettes by feeding the material to roll presses. After
the sheet exits from the roll presses, it is subjected to impact
devices which creates impact forces on opposing sides of the sheet
and wherein the opposed impact devices are positioned into parallel
overlapping relationship with each other at the plane of the sheet
exit and spaced from each other a distance corresponding to the
distance between parallel briquette pockets in the briquetting
machine. The impact forces are applied to separate briquettes on
opposing sides at different points of the sheet. One force is
applied to one briquette, while the force from the opposite
direction is applied to another parallel briquette. By applying
these forces to the briquettes, there is a large moment created at
the interconnecting webs, this tends to give a clean sharp break
along the leading edge of the briquette and may even completely
break away the briquette. The continued extension of the forces
across the sheet width will cause the broken briquettes to be
removed or partially broken briquettes to bend sharply away from
the sheet and complete the tearing around the periphery of the
briquette. These broken briquettes are then removed by the motion
of the impacting devices.
After the briquette is broken out from the sheet, it is then sent
to a tumbler device, a trommel, where its sharp edges are removed.
The smooth surfaced briquette then may be used in a furnace.
Loose material suitable for the practice of this invention may be
any of the types commonly briquetted: minerals, ores, carbons,
fines, flue dusts, etc. Iron ore fines and reduced iron ore fines
are of particular interest for briquetting at temperatures above
about 1400.degree.F. With hot reactive materials, such as hot iron
fines, carbon or char fines, an inert atmosphere, e.g. N.sub.2, is
desirable for briquetting.
Roll presses may have from about 20 to about 350 tons of pressure
for shaping the loose material in the D-shaped roll pockets. There
may be 1, 2, 3, 4 or more pockets across the roll surface. Each
pocket is offset from its adjacent pocket by about one-half the
length of the pocket. Next adjacent pockets are parallel to each
other.
As the sheet of D-shaped briquettes leaves the press rolls, the
impact forces are applied simultaneously to opposite sides of the
sheet. When there are next adjacent briquettes, these forces are
applied to these briquettes. One briquette receiving the impact
upon the convex portion of the D, the other receiving the impact
upon the flat side of the D. The impact will sever the web
surrounding the briquettes. As the forces are continually applied,
the briquette is pushed through and away from the sheet, resulting
in the briquette being broken away from the sheet. The distance
between the points of force application allow the broken out
briquette to fall away. As the sheet advances, the successive
forces may be applied to briquettes on alternate sides of the sheet
center line. This improves a clean separation of the briquettes one
from another and from the sheet.
Applying forces in this manner causes the simultaneous separation
of a briquette from its strand and from its row in the sheet. FIG.
3 illustrates a sheet as it advances through the zone of force
application. After the leading parallel briquettes are broken away,
the adjacent briquettes are left with only the part of its
surrounding web intact. As these briquettes are broken away, the
succeeding briquettes likewise have only a partial web left, which
connects them to the sheet.
The forces may be applied to the region from the center of the
D-shape (top dead center) to the trailing edge of the briquette in
the sheet. If the point of application is rearward of top dead
center, then there is an additional forward thrust to break the
briquette from the sheet.
The minimum force necessary to break the briquette from the sheet
depends upon the nature of the material and the thickness of the
web. With iron ore or partially reduced iron ore, the loose
material is preferably at temperatures in excess of 1000.degree.F,
particularly 1500.degree. - 2000.degree.F, because this gives
improved briquette strength and the sheet is weaker than at lower
temperatures. High temperature impact sampling of the particular
sheet material will indicate the necessary minimum force to be
used.
A briquetting apparatus according to the invention is illustrated
in FIGS. 1 and 2. Loose material is fed to the briquetting machine
1. The press rolls 11 convert it into a sheet of briquettes 12. As
shown in FIG. 3, the sheet 12 has briquettes 30 connected to each
other by lands 31. This shows the spacing of adjacent and next
adjacent briquettes. The D-shaped briquettes are shown in FIG. 4 in
profile. The web formed by the lands 31 may be about 0.1 to 0.3
inch thick. The briquettes may be about 1 to 3 inches in length,
about 0.5 to 1 inch thick and about 0.5 to 1 inch wide. The
briquette sizes are selected according to the ultimate intended
use. For iron or iron ore briquettes, lengths of about 1 inch are
preferred.
The sheet of briquettes 12 then enters between opposing impact
devices here shown as having shafts 18 and 19 to support cylinders
14 and 15 with impact means 16 and 17 mounted thereon, said support
cylinders being axially aligned with the length of the sheet exit.
Here, the impact means are shown as solid members attached to the
cylinder support. The impact free of the member is chamferred on
its sides and may be hardened. As shown in FIG. 2, the opposing
impact devices have their impact means disposed to contact next
adjacent briquettes in the sheet. On each of the devices,
successive impact means are staggered from each other so that as
the impact device moves, the impact forces can be applied on
alternate sides of the briquette sheet centerline.
In the practice of this invention, the impact devices must be
sufficiently rugged to withstand the impact force generated when
the impact means strike the briquette sheet. Moreover, the devices
are exposed to high temperature during the briquetting operation.
An impact device in the form of a cylinder having mounted thereon
impact means in the form of solid members will operate
satisfactorily under these conditions. The impact means may be
round or polygonal in cross-section, especially oval or
rectangular. Other forms of the impact device include stationary
frames with reciprocating drives to propel impact means in the form
of solid shafts transversely to the direction of the briquette
sheet. For all of the impact devices, the clearances and sequence
of operation of the impact means are such that the simultaneous
impact forces are applied on opposite sides of the briquette
sheet.
The impact means are spaced from each other and move at a rate
determined by the speed of the briquette sheet. The impact means
when normal to the sheet extend across the thickness of the
briquette sheet. The spacing of the impact means on opposing impact
devices provides clearance for discharge of briquettes broken away
from the sheet. The staggered arrangement of impact means on an
impact device permit the machine to be self-cleaning. If briquettes
or pieces of briquette sheets fall into the space between impact
means, the motion of the succeeding impact means will tend to clear
the spacing.
On each impact device, the impact means are coordinated with the
impact means of the opposite device so that when the sheet is
struck, the impact forces are delivered on parallel next adjacent
briquettes. If there are two such briquettes, each device will have
one impact means contacting the sheet at the same time. If there
are more than two such briquettes, then the total number of impact
means striking the sheet will be equal to the sum of this number.
The means on each device will still be disposed to deliver forces
on opposite sides of the sheet to parallel next adjacent
briquettes.
A housing 13 encloses the input means of the briquetting machine.
This housing may be used to enclose an inert atmosphere such as
nitrogen when materials reactive at the briquetting temperatures
are processed.
A specific illustration of this invention is as follows:
Iron ore is treated to remove at least about 75 percent of its
oxides and transferred at a temperature of about 1600.degree.F to a
pair of briquetting roll presses. These rolls form a sheet having
four briquettes across its width. These briquettes are about 1 inch
in length, 0.5 inch wide and 0.5 inch radius. About 33 briquette
rows per second are made. The briquette sheet has a web thickness
of about 0.1 inch. This sheet travels at a speed of about 53 inches
per second. The sheet is passed between opposing cylinders. The
cylinders have a diameter of about 10 inches and are centered on
opposite sides of the sheet and having the axes of the cylinders
lying in the same plane and positioned about 15 inches apart. Under
the aforesaid circumstances these cylinders are driven by external
motors at a speed of 671 rpm. This speed may vary from about 250 to
750 rpm depending upon the briquette sheet speed and the number of
impact means. There are six steel pins mounted equi-distant about
the periphery of each cylinder. These pins are rectangular in cross
section at about 2 inches on a side. These pins are about 3 inches
in height, having chamferred sides adjacent the outer face. The
face is about 1 inch on each side. These pins are staggered from
each other along the periphery. On the one cylinder, these pins are
aligned adjacent each other on each side of the sheet centerline.
On the opposing cylinder, these pins are staggered so that they
contact the briquettes along the outside edge of the briquette
sheet, i.e. their centerlines are about 5.5 inches apart measured
across the cylinder. When the pins of opposing cylinders are
parallel to each other and normal to the plane of the sheet, the
faces will extend about 0.4 inch beyond the mid-section of the
sheet. The cylinders are rotated upon their shafts and the impact
face of the pins first contact the briquettes at about top dead
center. Separated briquettes fall onto the conveyor which carries
them to a tumbler where residual sharp edges are removed.
A particular advantage of this invention is that broken pieces of
briquette sheet will pass through the impacting devices without
causing jamming of the devices. Usually, the broken sheet is of
sufficient size to be engaged by the impacting devices where the
action of the impacting forces will break it into its separate
briquettes. Moreover, if the sheet of briquettes as it issues from
the press rolls, tends to curve away from a straight path, the
opposed impact devices will align it to be subject to the impact
forces whose motion will break out the briquettes. Where portions
of sheet have fallen past the impact devices without breaking, they
may be recycled directly to the impacting devices via conveyors and
chutes which will align these sheets and feed them directly into
the impacting devices for briquette separation.
While our invention has been described in terms of specific
components, materials and steps, variations and additions in
structure or procedure as would be apparent to one skilled in the
art are equally within the spirit of our invention.
* * * * *