U.S. patent application number 12/966068 was filed with the patent office on 2012-06-14 for hydraulic distributor for top charging a blast furnace.
This patent application is currently assigned to WOODINGS INDUSTRIAL CORPORATION. Invention is credited to Brayton CARNER, Alan COLUCCI, Donald HOWELL.
Application Number | 20120148373 12/966068 |
Document ID | / |
Family ID | 46199562 |
Filed Date | 2012-06-14 |
United States Patent
Application |
20120148373 |
Kind Code |
A1 |
HOWELL; Donald ; et
al. |
June 14, 2012 |
HYDRAULIC DISTRIBUTOR FOR TOP CHARGING A BLAST FURNACE
Abstract
A hydraulic distributor for safely and efficiently top charging
a bell-less blast furnace. The hydraulic distributor includes a
main housing, an inner ring, a trunnion, and an actuator ring,
which act together to lift and rotate the distributor chute.
Hydraulic tilt cylinders operatively coupled to the inner ring act
to lift the distributor chute to change tilt. Rotational Drives
operatively coupled to the trunnion act to rotate the distributor
chute. The hydraulic distributor provides improved repeatability
and precision control of the distributor chute, and hence the
placement of burden materials within the blast furnace resulting in
improved productivity and operation of the furnace. The hydraulic
distributor provides a less complex design and construction
resulting in reduced costs for manufacturing and maintenance.
Inventors: |
HOWELL; Donald; (McMurray,
PA) ; COLUCCI; Alan; (Allison Park, PA) ;
CARNER; Brayton; (Cranberry Township, PA) |
Assignee: |
WOODINGS INDUSTRIAL
CORPORATION
Mars
PA
|
Family ID: |
46199562 |
Appl. No.: |
12/966068 |
Filed: |
December 13, 2010 |
Current U.S.
Class: |
414/199 ;
414/804 |
Current CPC
Class: |
C21B 7/20 20130101; F27D
3/10 20130101; F27B 1/20 20130101 |
Class at
Publication: |
414/199 ;
414/804 |
International
Class: |
C21B 7/20 20060101
C21B007/20 |
Claims
1. A hydraulic distributor comprising: a housing comprising a top
cover plate, a bottom and a sidewall extending between the top
cover plate and the bottom; an inner ring located in the housing; a
trunnion located with the housing and concentrically inward from
the inner ring, and an actuator ring located with the housing and
concentrically between the inner ring and the trunnion; a hydraulic
tilt cylinder mounted to the top cover plate of the housing; the
hydraulic tilt cylinder comprising a hydraulic cylinder, a cylinder
stand and a cylinder rod, the cylinder rod extending into the
housing and operatively coupled to the inner ring; a rotational
drive mounted to the top cover plate of the housing; the rotational
drive comprising a motor, a pinion drive shaft, and a drive pinion,
the pinion drive shaft and drive pinion extending into the housing
and operatively coupled to the trunnion; a distributor cradle
operatively coupled to the inner ring, the trunnion, and the
actuator ring; a distribution chute mounted to the distributor
cradle wherein linear movement of the hydraulic tilt cylinder
serves to lift and control tilt of the distribution chute and
wherein rotational movement of the rotational drive serves to
rotate the distributor chute.
2. The hydraulic distributor of claim 1, further comprising four
hydraulic tilt cylinders positioned about 90 degrees apart from one
another.
3. The hydraulic distributor of claim 1, wherein the inner ring is
connected to the actuator ring using a lower roller slewing
bearing, the lower bearing connection allowing the actuator ring to
rotate in a continuous 360 degree motion and move up and down based
on the movements of the inner ring.
4. The hydraulic distributor of claim 3, wherein the actuator ring
is connected to one or more pivoting crank shafts having linkage,
crank arms and roller assemblies, wherein the rollers and crank
arms force the crank shafts to pivot as the actuator ring moves up
or down, this crank arms to crank shaft connection transferring the
vertical motion into a horizontal rotation motion that in turn
tilts the distribution chute up of down.
5. The hydraulic distributor of claim 4, wherein the crank shafts
pivot on a set of bushings located in a trunnion inner most ring,
the other end of the crank shafts connected to the distribution
chute cradle.
6. The hydraulic distributor of claim 1, further comprising two
rotational drives positioned about 180 degrees apart from one
another, wherein during normal operations one rotational drive is
operating and the other rotational drive is in stand-by.
7. The hydraulic distributor of claim 1, wherein the rotational
drive pinion is coupled to the trunnion via an upper geared slewing
bearing, the trunnion is bolted to an outside externally geared
race of the slewing bearing, an inside race of the slewing bearing
is connected to the hydraulic distributor housing and is
stationary, the upper bearing connection transferring the rotation
motion from the rotation drive to the trunnion.
8. The hydraulic distributor of claim 7, wherein as the trunnion
rotates, crank shafts mounted through the trunnion rotate about the
vertical centerline of the hydraulic distributor, the crank shafts
are connected to and rotate the distribution chute cradle.
9. The hydraulic distributor of claim 1, further comprising a
control system for controlling rotation and tilt of the hydraulic
distributor.
10. The hydraulic distributor of claim 9, wherein the hydraulic
tilt cylinder further comprises a linear transducer, wherein the
linear transducer provides a precise location of the cylinder rod
stroke to the control system.
11. The hydraulic distributor of claim 9, wherein rotational drive
further comprises an encoder internal to the motor, wherein the
encoder is used by the control system to determine distributor
chute rotation angle.
12. The hydraulic distributor of claim 9, further comprising a
source of hydraulic pressure in fluid communication with the
hydraulic cylinder of the hydraulic tilt cylinder, wherein the
source of hydraulic pressure is controlled by the control system to
cause extension or retraction of the hydraulic tilt cylinder and
control lift of the distributor chute.
13. The hydraulic distributor of claim 1, further comprising
electronics electrically connected to the rotational drive, wherein
the electronics are controlled by the control systems to activate
the rotational drive to control rotation of the distributor
chute.
14. The hydraulic distributor of claim 1, further comprising a
linear transducer in each of the hydraulic cylinders that provide a
precise location of the cylinder stroke, wherein the location of
the cylinder stroke dictates the angle of the distribution
chute.
15. The hydraulic distributor of claim 1, further comprising an
encoder in the rotational drive motor that provides precise
location of the rotation drive, wherein the location of the
rotation drive dictates a rotational angle of the distribution
chute.
16. A method of controlling the rotation and tilt of a distributor
chute of a hydraulic distributor comprising: controlling
distribution chute rotational motion by: utilizing a rotation drive
having a motor; energizing the motor to rotate an output shaft of
the motor; operatively coupling a gear reducer to the motor output
shaft; coupling a shaft to the gear reducer, the shaft having a
drive pinion keyed to the shaft, wherein the gear reducer transmits
the rotation of the motor output shaft to cause rotation of the
drive pinion; rotating an upper roller slewing bearing that is
operatively coupled to the drive pinion; connecting a trunnion to
the slewing bearing, wherein the bearing connection transfers the
rotation motion from the rotation drive to the trunnion; as the
trunnion rotates, rotating crank shafts mounted through the
trunnion about a vertical centerline of the hydraulic distributor;
connecting a distribution chute cradle the crank shafts; rotating
the distribution chute cradle as the crank shafts rotate about the
vertical centerline of the hydraulic distributor; connecting a
distribution chute to the distribution chute cradle, so as the
cradle rotates the distribution chute rotates as well; controlling
distribution chute tilt motion by: utilizing hydraulic cylinders
connected to a source of hydraulic pressure; connecting the
hydraulic cylinders to an inner ring inside a hydraulic distributor
housing via connecting rods; extending and retracting the hydraulic
cylinder to move the inner ring in a vertical up and down motion;
connecting the inner ring to an actuator ring through a connection
using a lower roller slewing bearing, wherein the bearing connect
is designed to allow the actuator ring the ability to rotate in a
continuous 360 degree motion and move up and down based on the
movements of the inner ring; connecting the actuator ring to two
pivoting crank shafts utilizing linkage, crank arms and rollers,
the rollers and crank arms force the crank shafts to pivot as the
actuator ring moves up or down, this crank arms to crank shaft
connection transferring the vertical motion, up and down, into a
horizontal rotation motion that in turn tilts the distribution
chute up or down.
17. The method of claim 16, wherein the upper slewing bearing is an
externally geared X style roller slewing bearing, and further
comprising; connecting the trunnion to an outside externally geared
race of the slewing bearing; and connecting an inside race of the
slewing bearing to the hydraulic distributor housing.
18. The method of claim 16, further comprising pivoting the crank
shafts on a set of bushings located on the trunnion, and the other
end of the crank shafts being connected to the distribution chute
cradle.
19. The method of claim 16, further comprising connecting the inner
ring to the actuator ring using a lower roller slewing bearing, the
lower bearing connection allowing the actuator ring to rotate in a
continuous 360 degree motion and move up and down based on the
movements of the inner ring.
20. The hydraulic distributor of claim 19, further comprising
connecting the actuator ring to one or more pivoting crank shafts
having linkage, crank arms and roller assemblies, wherein the
rollers and crank arms force the crank shafts to pivot as the
actuator ring moves up or down, this crank arms to crank shaft
connection transferring the vertical motion into a horizontal
rotation motion that in turn tilts the distribution chute up of
down.
Description
TECHNOLOGY FIELD
[0001] The present invention relates in general to blast furnaces,
and more particularly, to a hydraulic distributor for top charging
a blast furnace.
BACKGROUND
[0002] A blast furnace is a type of metallurgical furnace used for
smelting to produce industrial metals. In a typical blast furnace,
fuel and metal ore are continuously supplied through the top of the
furnace and air is blown into the bottom of the chamber. Chemical
reactions take place throughout the furnace as the material moves
downward. The end products are typically molten metal and slag
phases tapped from the bottom of the furnace, and flue gases
exiting from the top of the furnace. One conventional use of a
blast furnace is for smelting iron ore to produce pig iron, an
intermediate material used in the production of commercial iron and
steel.
[0003] Modern furnaces are equipped with an array of supporting
facilities to increase efficiency. The various raw or burden
materials are weighed to yield the desired hot metal and slag
chemistry. The raw materials are introduced into the furnace
through the top of the blast furnace. There are different ways in
which the raw materials may be charged into the blast furnace. For
example, some blast furnaces use a "double bell" system where two
"bells" are used to control the entry of the raw material into the
blast furnace. The purpose of the two bells is to minimize the loss
of hot gases in the blast furnace. First the raw materials are
emptied into the upper or small bell. The bell is then rotated a
predetermined amount in order to distribute the charge more
accurately. The small bell then opens to empty the charge into the
large bell. The small bell then closes, to seal the blast furnace,
while the large bell dispenses the charge into the blast
furnace.
[0004] A more recent design is to use a "bell-less" system. A
bell-less system uses multiple hoppers to contain each raw
material, which is then discharged into the blast furnace through
valves. The hopper system with valves are more accurate at
controlling how much of each constituent is added, as compared to a
conventional bell type system, thereby increasing the efficiency of
the furnace. Further, some of these bell-less systems also
implement a chute in order to precisely control where the charge is
placed.
[0005] The charging procedure is an important means for influencing
the gas distribution and performance of the furnace. Proper
distribution of the burden materials entering the top of the blast
furnace is essential to efficient operation of the furnace. Various
designs exist for the burden charging process. For example: gimbal;
top-charger; roto-charger; bell top, rotating chute, etc.
[0006] Conventional rotating chute designs use a complex and
sensitive planetary gearbox for tilt and rotation. One such
conventional electro/mechanical design is the Model PW bell-less
top charging equipment. This conventional design includes multiple
moving parts and is complicated to design and manufacture. Also,
these conventional rotating chute designs have complex cooling
systems. In addition, conventional rotating chute designs have
sensitivity of tilting gearboxes for extreme positions and for
lubrication. All this leads to higher cost for manufacturing and
maintenance.
[0007] What is needed is a hydraulic distributor for a blast
furnace that meets one or more of the following short comings in
conventional blast furnaces: improves the control of the
distribution of burden materials within a blast furnace; exceeds
conventional gearbox capacities; improves repeatability and
precision of chute positions; reduces complex components; reduces
manufacturing and maintenance costs; improves bearing design;
simplifies the chute change process; reduces refractory lined
rotating mass; provides an efficient cooling system; and/or
improves redundancy for rotation and tilt.
SUMMARY
[0008] Embodiments of the present invention address and overcome
one or more of the above shortcomings and drawbacks, by providing
devices, systems, and methods for safely and efficiently top
charging a blast furnace. This technology is particularly
well-suited for, but by no means limited to, a bell-less blast
furnace. The hydraulic distributor for a blast furnace according to
embodiments of the present invention provides an improvement over
prior designs, including improved repeatability and precision
control of the distributor chute and hence the placement of
materials within the furnace. The hydraulic distributor provides a
less complex design and construction, as compared to convention
electro/mechanical gear designs, resulting in reduced costs for
manufacturing and maintenance.
[0009] The hydraulic distributor of the present invention helps
ensure proper distribution of the burden materials entering the top
of the blast furnace thereby improving the performance and
efficiency of the blast furnace operation. The hydraulic
distributor provides for controlled, systematic charging resulting
in improved productivity and operation of the furnace.
[0010] According to one embodiment of the invention, a hydraulic
distributor for a bell-less top gearbox of blast furnace is
provided. The hydraulic distributor includes a main housing or
shell, an inner ring, a trunnion, and an actuator ring. The inner
ring, trunnion, and actuator ring are located within the main
housing and are operatively coupled to one another to effectuate
rotation and tilt of a distributor chute coupled to the hydraulic
distributor via a chute cradle. The inner ring acts to lift the
distribution chute. The trunnion acts to rotate the distributor
chute. The actuator ring acts to lift and rotate the distributor
chute.
[0011] A control system, electronics and hydraulics are provided to
control the operation of the hydraulic distributor. For example,
the control system controls the electronics and hydraulics to
manipulate the movement of the inner ring 110, trunnion 120, and
actuator ring 130, which in turn cause tilt and rotation the
distributor chute 102, as desired. For example, the control system
may be programmed with a burden distribution model for a particular
blast furnace (or smelting process) to precisely control the
placement of burden material within the furnace.
[0012] Hydraulic tilt cylinders assemblies are provided to control
the angle (or tilt) of the distribution chute. The angle (or tilt)
of the distributor chute may be controlled by hydraulic cylinder
stroke. Linear transducers in the hydraulic cylinders give a
precise location of the cylinder stroke. This position dictates the
angle of the distribution chute. The hydraulic tilt cylinders
provide repeatability of the same angle at the correct
position.
[0013] The hydraulic tilt cylinders are mounted to the top and
outside of the hydraulic distributor housing and connecting rods
extend into the main housing to link the hydraulic cylinders to the
inner ring. The hydraulic cylinders extend and retract causing the
inner ring to move down and up, respectively.
[0014] In one embodiment, the inner ring is connected to the
actuator ring through a connection using a roller slewing bearing.
The bearing connect is designed to allow the actuator ring the
ability to rotate in a continuous 360 degree motion and move up and
down based on the movements of the inner ring. The actuator ring is
then connected to pivoting crank shafts by utilizing appropriate
linkage, crank arms, and roller assemblies. The rollers and crank
arms force the crank shafts to pivot as the actuator ring moves up
or down. This crank arms to crank shaft connection transfers the
vertical motion, up and down, into a horizontal rotation motion
that in turn tilts the distribution chute up or down. In one
embodiment, the crank shafts pivot on a set of bearings located in
the trunnion ring with a fixed connection to the cradle. The other
end of the crank shafts may be connected to the actuator ring. The
distribution chute is connected to the distribution chute cradle.
As the crank shafts tilt the distribution chute cradle, the cradle
tilts the distribution chute.
[0015] Rotational drive assemblies control the rotation of the
chute. Chute rotation may be accomplished with a gear motor and
pinion that drives a geared slewing bearing at a constant RPM. An
encoder internal to the rotation drive motor may be used to
determine and control chute rotation angle.
[0016] The rotation drives are is mounted to the top and outside of
the hydraulic distributor housing. In one embodiment, the rotation
drive 140 has a motor 141 that may be operatively coupled to a gear
reducer. The gear reducer may be coupled to a shaft with a drive
pinion keyed to the shaft that extend into the housing. The drive
pinion rotates an externally geared roller slewing bearing. The
trunnion may be bolted to the outside externally geared race of the
slewing bearing. The bearing connection transfers the rotation
motion from the rotation drive to the trunnion. The inside race of
the slewing bearing is stationary and may be bolted to the
hydraulic distributor housing.
[0017] As the trunnion rotates, the crank shafts mounted through
the trunnion then rotate about the vertical centerline of the
hydraulic distributor. The crank shafts may be connected to the
distribution chute cradle. As such, the distribution chute cradle
rotates as the crank shafts are rotating about the vertical
centerline of the hydraulic distributor. Rotation of the
distribution chute cradle rotates the distribution chute.
[0018] According to one aspect of the invention, the hydraulic
distributor provides for redundancy of operation. For example, the
hydraulic distributor may include multiple and redundant rotational
drive assemblies for rotating the chute. For example, the hydraulic
distributor may include multiple and redundant hydraulic cylinder
assemblies for tilting the chute.
[0019] According to another aspect of the invention, the ease of
maintenance. For example, rotational drive assemblies are mounted
to the top cover plate of the hydraulic distributor allowing for
ease of access and/or replacement. For example, hydraulic cylinder
assemblies are mounted to the top cover plate of the hydraulic
distributor allowing for ease of access and/or replacement.
Further, the location of the hydraulic cylinder assemblies on the
outside of the hydraulic distributor also facilitates easier
calibration of the hydraulic cylinders.
[0020] According to another embodiment of the invention, the
hydraulic distributor simplifies the chute change process. For
example, the distribution chute may include an improved chute
cradle design and chute access door in a top portion of the blast
furnace to allow the chute to be repaired or replaced without
having to enter the hydraulic distributor. Also, the distribution
chute may be designed to simply insert into the cradle, so that no
pins are required. Also, tilt lockout pins may be provided to lock
the chute in position and prevent tilt movement.
[0021] In some embodiments of the invention, the hydraulic
distributor is manufactured using substantially all fabrication
techniques. In other embodiments, the hydraulic distributor is
designed and manufactured as a standard unit (e.g., standard size
and dimensions). A standardized design allows the hydraulic
distributor to easy replace a conventional gearbox and allows the
hydraulic distributor to be placed in the identical same location
as a conventional gearbox in which it is replacing. A standardized
hydraulic distributor also provides the advantage of having
substantially the same burden distribution characteristics as the
gearbox it is replacing.
[0022] In some embodiments of the invention, the hydraulic
distributor includes an improved and more reliable cooling system.
The cooling system may include a simple once through water system.
The cooling system may include a shower cooled system.
[0023] In some embodiments of the invention, the hydraulic
distributor includes an improved and more reliable nitrogen system.
The nitrogen system may include nitrogen that is injected at a
regulated pressure into the hydraulic distributor housing at a
pressure higher than the top pressure of the blast furnace to
prevent blast furnace gas from entering the hydraulic distributor.
In emergency situations, the nitrogen system may be used as an
emergency backup for cooling the hydraulic distributor.
[0024] Additional features and advantages of the invention will be
made apparent from the following detailed description of
illustrative embodiments that proceeds with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The foregoing and other aspects of the present invention are
best understood from the following detailed description when read
in connection with the accompanying drawings. For the purpose of
illustrating the invention, there is shown in the drawings
embodiments that are presently preferred, it being understood,
however, that the invention is not limited to the specific
instrumentalities disclosed. Included in the drawings are the
following Figures:
[0026] FIG. 1 shows an exemplary blast furnace on which embodiments
of the hydraulic distributor of the present invention may be
used;
[0027] FIG. 2 shows an exemplary hydraulic distributor installed
over a blast furnace in accordance with one embodiment of the
invention;
[0028] FIG. 3 is a top view showing the general arrangement of an
exemplary hydraulic distributor;
[0029] FIG. 4 is a side view taking along line 4-4 of FIG. 3;
[0030] FIG. 5 is a side view taking along line 5-5 of FIG. 3 and
rotated 90 degrees from the view of FIG. 4;
[0031] FIG. 6 is a cross-sectional view taking along line 6-6 of
FIG. 3;
[0032] FIG. 7 is a cross-sectional view taking along line 7-7 of
FIG. 3 and rotated 90 degrees from the view of FIG. 6;
[0033] FIG. 8 is a cross-sectional view taking along line 8-8 of
FIG. 4;
[0034] FIG. 9 is a partial cross-sectional view taking along line
9-9 of FIG. 3 showing an exemplary hydraulic tilt cylinder;
[0035] FIG. 10 is a partial cross-sectional view taking along line
10-10 of FIG. 3 showing exemplary alignment key travel;
[0036] FIG. 11 is a partial cross-sectional view taking along line
11-11 of FIG. 3 showing an exemplary lock-out pin in the unlocked
position;
[0037] FIGS. 12A and 12B are partial cross-sectional views taking
along line 12-12 of FIG. 3 showing the distribution chute at
maximum angle and minimum angle, respectively;
[0038] FIGS. 13A, 13B, and 13C are top, side and cross-sectional
views, respectively, of an exemplary shell assembly;
[0039] FIGS. 14A and 14B are top and side views, respectively, of
an exemplary inner ring assembly;
[0040] FIGS. 15A, 15B, and 15C are top and two side views,
respectively, of an exemplary trunnion assembly;
[0041] FIGS. 16A and 16B are top and cross-sectional views,
respectively, of an exemplary actuator ring assembly;
[0042] FIGS. 17A and 17B are top and side views, respectively, of
an exemplary deflector ring assembly;
[0043] FIGS. 18A and 18B show an exemplary rotational drive
assembly and details thereof;
[0044] FIGS. 19A and 19B show an exemplary hydraulic tilt cylinder
assembly in the retracted and extended positions, respectively;
[0045] FIGS. 20A and 20B are side and cross-sectional views,
respectively, of an exemplary distributor chute cradle;
[0046] FIGS. 21A and 21B are top and cross-sectional views,
respectively, of an exemplary feeder spout assembly;
[0047] FIGS. 22A, 22B, and 22C are top, side and cross-sectional
views, respectively, of an exemplary hydraulic distributor
hydraulic piping arrangement;
[0048] FIGS. 23A, 23B, 23C, and 23D are top, side, end and
cross-sectional views, respectively, of an exemplary distributor
chute;
[0049] FIGS. 24A-24D show a jig tool and exemplary method for
replacing the chute;
[0050] FIG. 25 shows an exemplary water cooling system; and
[0051] FIGS. 26A and 26B show an exemplary roller assembly.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0052] The above problems in the prior art have motivated the
creation of a hydraulic distributor for a blast furnace that solves
one or more of the above-identified problems or shortcomings of
conventional blast furnaces. The hydraulic distributor receives and
distributes burden material (also referred to as raw material)
inside a blast furnace. In particular, the hydraulic distributor,
according to embodiments of the invention, precisely distributes
burden material in a specific area within the furnace, which makes
the process work better. This is accomplished through the improved
control of the rotation and tilt of the distributor chute.
[0053] In some embodiments, the hydraulic distributor is for a
bell-less top gearbox of a blast furnace. The hydraulic distributor
eliminates the complex planetary gear box for lift and rotation of
the distributor chute and provides one or more advantages over
conventional gear box designs. For example, the hydraulic
distributor improves repeatability of chute positions for charging
ring locations. For example, the hydraulic distributor improves
revolution speed of chute position changes. For example, the
hydraulic distributor provides redundancies for rotation and tilt.
For example, the hydraulic distributor improves bearing
configuration. For example, the hydraulic distributor is easier to
maintain than conventional gearboxes. For example, the hydraulic
distributor reduces maintenance costs though reduced complexity and
ease of access of components. For example, the hydraulic
distributor provides externally mounted hydraulic cylinders. For
example, the hydraulic distributor provides externally mounted
rotational drives. For example, the hydraulic distributor provides
for external tilt angle calibration. For example, the hydraulic
distributor simplifies the water cooling system. For example, the
hydraulic distributor allows for a heavier distribution chute. For
example, the hydraulic distributor simplifies the chute change or
replacement. For example, the hydraulic distributor has an improved
ability to withstand top temperature and pressure requirements
under normal blast furnace operations and during excursions.
[0054] To achieve the requirements for reliability, repeatability
and low maintenance cost the hydraulic distributor design of the
present invention uses hydraulic technology in place of
conventional electro-mechanical technology. Use of hydraulic
technology to control the distribution chute position (e.g.,
rotation and tilt) provides a number of advantages in comparison to
the conventional gearbox design that utilizes complex mechanical
gearing and mechanical brakes.
[0055] The hydraulic distributor comprises a future generation of
blast furnace charging systems. Essentially, the hydraulic
operation results in a stronger more compact design with a more
reliable operation that produces more accurate and repeatable chute
positions with less maintenance. Also, the hydraulic distributor
does not have to rely on limit switches at the end positions of
travel, since this position is dictated by the cylinder stroke. A
limitation of conventional non-hydraulic designs is that if limit
switches do not work, the device runs through the end positions
resulting in mechanical damage to the equipment.
[0056] The angle (or tilt) of the distribution chute may be
controlled by hydraulic cylinder stroke. Linear transducers in the
hydraulic cylinders give a precise location of the cylinder stroke.
This position dictates the angle of the distribution chute. This
hydraulic distributor system results in the repeatability of the
same angle at the correct position. Also, the design of the
hydraulic valve system holds this position and provides a fast
response to changes in chute positions. The hydraulic distributor
design eliminates relying on brakes to stop the chute and
eliminates differences from chute angle due to gear wear. In
addition, the hydraulic cylinders are located on the exterior of
the hydraulic distributor thereby allowing the chute angles to be
calibrated without stopping the furnace by determining the stroke
position of the cylinders.
[0057] The rotation of the chute may be accomplished with a gear
motor and pinion that drives a geared slewing bearing at a constant
RPM. In some embodiments, the hydraulic distributor may be supplied
with two rotation drive assemblies, one operating and one standby.
An encoder internal to the rotation drive motor may be used to
determine and control chute rotation angle.
[0058] FIG. 1 shows an exemplary blast furnace 10. As shown, the
blast furnace 10 may include a preheating zone 12, a first
reduction zone 14 (e.g., for the reduction of ferric oxide), a
second reduction zone 16 (e.g., for the reduction of ferrous
oxide), and a melting zone 18. One or more sources of hot blasts 20
are provided. For example, BF stoves may supply hot blasts to the
melt zone 18. A feeder 22 supplies raw materials into the top
opening 24 of the blast furnace 10. The feeder 22 may include, for
example, a belt, a conveyor, a conduit, tracks with cars, rails
with hoppers, a bridge, transfer cars, and the like. During
operation, exhaust gases collect in a top portion or dome of the
furnace and an uptake 26 may be provided for the removal of gases
from the blast furnace 10. Taps 28a, 28b and conduits 30a, 30b may
be provided for the removal of slag and molten metal (e.g., pig
iron), respectively, from the furnace 10.
[0059] For example, an iron making blast furnace may comprise a
tall chimney-like structure lined with refractory brick 32. Coke,
limestone flux, and iron ore (iron oxide) may be charged into the
top of the furnace in a precise filling order which helps control
gas flow and the chemical reactions inside the furnace. Uptakes 26
allow the hot, dirty gas to exit the furnace dome, while bleeder
valves (not shown) may protect the top of the furnace from sudden
gas pressure surges. The coarse particles in the gas may settle in
the dust catcher (not shown) and may be discharged from the furnace
for disposal, while the gas itself may flow through a venturi
scrubber (not shown) and a gas cooler (not shown) to reduce the
temperature of the cleaned gas.
[0060] A casthouse 34 at the bottom half of the furnace may include
the bustle pipe, tuyeres and the equipment for casting the liquid
iron and slag. One or more tapholes may be drilled through the
refractory clay plug(s) allowing liquid iron and slag to flow down
a trough through a skimmer opening, separating the iron and slag.
Modern, larger blast furnaces may have multiple tapholes and
casthouses. Once the pig iron and slag has been tapped, the taphole
is again plugged with refractory clay, or other suitable
material.
[0061] Tuyeres may be used to implement a hot blast, which may be
used to increase the efficiency of the blast furnace. The hot blast
is directed into the furnace through water-cooled copper nozzles
called tuyeres near the base. Oil, tar, natural gas, powdered coal
and oxygen can also be injected into the furnace at tuyere level to
combine with the coke to release additional energy which is
necessary to increase productivity.
[0062] FIG. 2 is a general arrangement view showing the hydraulic
distributor 100 installed over a blast furnace, such as the
exemplary blast furnace 10 shown and described with reference to
FIG. 1. As shown in FIG. 2, the hydraulic distributor 100 is
installed over the top opening 24 of the blast furnace 10. The
hydraulic distributor 100 is used to lift and rotate a distributor
chute 102 in order to control the feed and distribution of raw
materials into the furnace 10.
[0063] As shown in FIG. 2, raw materials (not shown) may flow from
the feeder 22 and may gravity feed into a feed hopper 40 positioned
below the feeder to receive the raw materials. One or more material
hoppers (e.g., lock hoppers) 42 may be positioned below feed hopper
40 to receive the raw materials. Two material hoppers 42 are shown
in FIG. 2. Feed hopper 40 may be movable to selectively discharge
raw materials into a top opening 44 of one of the material hoppers
42. Each material hopper 42 also includes a bottom opening 46 for
allowing the raw materials to exit the material hoppers 42. A
material gate 48 and lower seal valve 49 may be provided at each
bottom opening 46 to control the flow of raw materials exiting each
material hopper 42. The lower seal 49 may be located in a lower
seal valve housing 50. As shown, an expansion joint 52 and a shut
off or goggle valve 54 may also be located between the material
hoppers 42 and the hydraulic distributor 100. A chute access door
56 is also provided in a top portion 58 of the blast furnace 10 for
maintenance and replacement of the chute.
[0064] FIGS. 3-8 show one embodiment of the hydraulic distributor
100. As shown in the figures, the hydraulic distributor 100
includes a housing or shell 104, an inner ring 110, a trunnion 120,
and an actuator ring 130. As shown, the inner ring 110 may be
located in housing 104 and serves to lift the distribution chute
102. As shown, the trunnion 120 may be positioned concentrically
within the inner ring 110 and is operatively coupled to the
actuator ring 130. The trunnion 120 serves to rotate the
distributor chute 102. Also as shown, the actuator ring 130 may be
positioned concentrically with the trunnion 120 and is operatively
coupled to the trunnion 120. The actuator ring 130 serves to lift
and rotate the distributor chute 102. The movement of the inner
ring 110, trunnion 120, and actuator ring 130 may be used to tilt
and rotate the distributor chute 102, as desired, based upon, for
example, the burden distribution model of the blast furnace.
[0065] As shown in FIGS. 3-5 and 13A-13D, the main housing 104
includes a bottom 105, a top cover plate 106, and a sidewall 107
extending between the bottom 105 and the top cover plate 106. Water
inlet ports 108a and water outlet ports 108b may be provided in
housing 104. Nitrogen ports 108c may also be provided in housing
104.
[0066] Access doors 109 are provided for allowing access to the
components housed in main housing 104. The access doors 109 may
include a hinged pivot, bolted flange connection and a packing seal
to provide quick open or closing action of the access doors 109. As
shown, the upper access doors may provide access to: the hydraulic
tilt cylinder 150/inner ring 110 connections; rotation drive
pinions 144 and the top slewing bearing 145a and actuator ring
grease reservoirs. As shown, two lower doors may provide access to:
crank shafts 180; crank arms 184; rollers assemblies 186 (see FIGS.
26A and 26B); crank shaft bushing grease reservoirs (not shown);
bottom slewing bearing 145b; and bottom water trough.
[0067] As shown in FIGS. 3-7 and 9-10, the hydraulic distributor
100 may include a number of openings in and mounting flanges on the
top cover plate 106. For example, four hydraulic tilt cylinder
openings and flanges for mounting the hydraulic tilt cylinder
assemblies 150 and two rotor drive openings and flanges for
mounting the rotor drive assemblies 140. In the illustrated
embodiment, the hydraulic tilt cylinders 150 and rotor drives 140
are bolted to the respective mounting flanges.
[0068] As shown in FIGS. 3, 6, 7, 8, and 21A-21B, the hydraulic
distributor 100 also includes a feeder spout assembly 160. The
feeder spout assembly 160 extends through the center region of the
hydraulic distributor 100. Raw materials are fed through the top
opening of the feeder spout assembly 160, pass through the
hydraulic distributor 100, and flow out of the feeder spout
assembly 160 and into the chute 102.
[0069] As shown in FIGS. 3, 6, 7, 8, and 21A-21B, the distribution
chute 102 is mounted to the cradle 103, which rotates and lifts the
distribution chute 102. The chute shell may be lined with liner
plate. These liner plates may comprise cast manganese steel. The
liner plates are a normal wear item and the distribution chute
typically needs to be replaced over time. To increase life of liner
plates, the chute rotation direction can be change from a CW to a
CCW rotation, or visa-versa, periodical so wear is even on all
sides.
[0070] As shown in the figures, the hydraulic distributor 100 also
includes one or more rotational drive assemblies 140 and one or
more hydraulic tilt cylinder assemblies 150. The rotational drive
assemblies 140 act to rotate the distributor chute 102. The
hydraulic tilt cylinder assemblies 150 act to lift the distributor
chute 102.
[0071] Multiple rotational drive assemblies 140 may be provided. As
shown, two rotational drive assemblies 140 may be positioned 180
degrees apart from one another and may be mounted to the top cover
plate 106 of the main housing 104. Mounting of the rotational drive
assemblies 140 allows for ease of maintenance or replacement of
rotational drives without entering the hydraulic distributor shell
104.
[0072] As shown in FIGS. 6 and 18, each rotational drive 140
includes a motor 141 connected to the hydraulic distributor 100 via
a base housing 147. An output shaft of the gear motor 141 drives a
motor drive pinion 144 through a gear reducer 142 and pinion drive
shaft 143.
[0073] In one embodiment, the rotational drive 140 may be powered
by a 10 HP AC, 480V, 3-phase, 1,800-RPM electrical motor with an
encoder internal to the motor. This encoder is used by the control
system (e.g., the PLC) to determine chute rotation angle.
[0074] Multiple hydraulic tilt cylinder assemblies 150 may be
provided. As shown, four hydraulic tilt cylinder assemblies 150 may
be positioned 90 degrees apart from one another and may be mounted
to the top cover plate 106 of the main housing 104. In one
embodiment shown in FIGS. 9-12B and 19A-19B, the hydraulic tilt
cylinder assemblies 150 may include a 3,000-PSI mill duty type
cylinder with a 4-inch bore.times.2-inch rod and 13-inch stroke.
Each hydraulic cylinder may have a linear transducer incorporated
into the blind end head. The linear transducer may be used by the
control system to determine chute tilt angle. The hydraulic
cylinders 150 may be mounted on the top cover plate 106, which
allows for ease of maintenance or replacement of cylinders without
entering the hydraulic distributor shell 104.
[0075] As shown in FIGS. 7, 9, 10, 19A and 19B, each hydraulic tilt
cylinder includes a hydraulic cylinder 151, an intermediate rod
152, and a cylinder stand 153. The hydraulic cylinder 151 is
connected to a source of hydraulic pressure (not shown) and causes
extension and retraction of the intermediate rod 152. The cylinder
stand 153 is used to mount the hydraulic cylinder 151 to the
hydraulic distributor 100. As shown, the hydraulic cylinder rod is
attached to an intermediate rod 152 and a clevis 155. A pin may be
used to connect clevis 155 to inner ring 110.
[0076] The hydraulic distributor 100 uses two types of motion to
control the distribution chute 102--tilt and rotation. The
following is an explanation of how an exemplary hydraulic
distributor controls tilt and rotation in one embodiment of the
invention.
[0077] The distribution chute tilt motion may be achieved as
follows: [0078] 1. The tilt motion is achieved by utilizing
hydraulic cylinders 150 to precisely locate and hold the chute
position. The cylinders are mounted to the top cover plate 106 and
are outside of the hydraulic distributor shell 104 to provide easy
access and maintenance to the cylinders. [0079] 2. Connecting rods
152 link the hydraulic cylinders 150 to the inner ring 110 inside
the hydraulic distributor shell 104. The inner ring 110 moves in an
up and down motion as the hydraulic cylinders 150 extend and
retract. [0080] 3. The inner ring 110 is then connected to an
actuator ring 130 through a connection using an X style roller
slewing bearing 145b (bottom slewing bearing). The bearing
connection is designed to allow the actuator ring 130 the ability
to rotate in a continuous 360 degree motion and move up and down
based on the movements of the inner ring 110. [0081] 4. The
actuator ring 130 is then connected to two (2) pivoting crank
shafts 180 by utilizing linkage, crank arms 184 and roller
assemblies 186. The rollers 186 and crank arms 184 force the crank
shafts to pivot as the actuator ring 130 moves up or down. This
crank arms 184 to crank shaft 180 connection transfers the vertical
motion, up and down, into a horizontal rotation motion that in turn
tilts the distribution chute 102 up of down. See FIGS. 7, 12A, and
12B. [0082] 5. The crank shafts 180 pivot on a set of bushings
located in the trunnion inner most ring. The other end of the crank
shafts 180 may be connected to the distribution chute cradle 103
using, for example, a spline connection. [0083] 6. The distribution
chute 102 is connected to the distribution chute cradle 103. As the
crank shafts tilt the distribution chute cradle 103, the cradle 103
tilts the distribution chute 102. See FIGS. 4-7 12A, 12B, 20A, 20B,
26A and 26B.
[0084] See FIGS. 3, 7, 9-12B, and 19A-19B.
[0085] In some embodiments, the minimum distribution chute angle is
about 3 degrees (offset from vertical). In some embodiments, the
maximum distribution chute angle is about 55 degrees (offset from
vertical). In some embodiments, the distribution chute tilt angle
change speed is about 3 degrees per second.
[0086] The distribution chute rotational motion may be achieved as
follows: [0087] 1. A rotation drive 140 is mounted to the top cover
plate 106 located outside and on top of the hydraulic distributor
shell 104. Once again this provides for easy maintenance to the
rotation drive assembly 140, if needed. The rotation drive 140 has
a motor 141 (e.g., a 10 HP electrical motor) that may be
operatively coupled to a gear reducer 142 (e.g., a vertical Cyclo
gear reducer). The gear reducer 142 may be coupled to a shaft 143
with a drive pinion 144 keyed to the shaft 143. [0088] 2. The drive
pinion 144 rotates an externally geared X style roller slewing
bearing 145a (upper slewing bearing). The trunnion 120 may be
bolted to the outside externally geared bearing of the slewing
bearing. The bearing connection transfers the rotation motion from
the rotation drive 140 to the trunnion 120. The inside race of the
slewing bearing is stationary and is bolted to the top cover plate
106. [0089] 3. As the trunnion 120 rotates, the crank shafts 180
mounted through the trunnion 120 then rotate about the vertical
centerline of the hydraulic distributor 100. [0090] 4. These crank
shafts 180 may be spline connected, for example, to the
distribution chute cradle 103. As such, as the crank shafts 180 are
rotating about the vertical centerline of the hydraulic distributor
100 the distribution chute cradle 103 rotates as well. [0091] 5.
The distribution chute 102 is connected to the distribution chute
cradle 103, so as the cradle 103 rotates the distribution chute 102
rotates as well.
[0092] See FIGS. 3, 6, and 7.
[0093] In the illustrated embodiment, there are two chute rotation
drives 140, each with a motor 141 and an integral gearbox 142, but
only one rotational drive is in service at any time. The second
rotational drive is a spare and is mechanically disengaged. In one
embodiment, the functioning chute rotation motor and gearbox drive
the chute with an effective overall gear reduction of approximately
217:1. The chute rotation motor may be powered via a variable
frequency drive (VFD). In one embodiment, the Accel/Decel ramps in
the VFD may be set at about 5 seconds; and during normal operation,
the chute may rotate at constant speed of about 8 RPM.
[0094] When homing, the chute may rotate at a slow speed,
approximately 0.1-0.8 RPM (which may be set via the HMI). The
normal operating speed and the homing speed can both be set from
the HMI. The direction of rotation may be selected through the HMI.
In normal operation, the direction of rotation may be reversed
periodically.
[0095] The hydraulic distributor includes a rotating chute with
chute slope control capabilities. A control system may be provided
to control the operation of the hydraulic distributor through
primarily hydraulics and electronics. Hydraulics are generally used
to move mechanical components while the electronics are generally
used to control the components. The control system may control
components of the hydraulic valve stand, the hydraulic distributor,
and a Human-Machine Interface (HMI). In a typical blast furnace
operation, rotational speed (e.g., motor speed) is constant, and
the angle (lift and tilt) of the distribution chute and the flow
rate of material may be adjusted.
[0096] In one embodiment the hydraulic distributor control system
may include a controller (e.g., an Allen-Bradley.RTM. ControlLogix
PLC with I/O) and two variable-frequency drives (VFDs) (e.g.,
Allen-Bradley.RTM. Powerflex 700 VFDs). The PLC may communicate
with the Powerflex 700 VFD via a control network (e.g.,
Controlnet).
[0097] The I/O may be controlled by a PLC which in turn may
communicate with the existing control system and the HMI via a
suitable communications protocol (e.g., Ethernet/IP). The I/O reads
all field devices and the logic may be solved in the PLC. The
rotational motor may include an encoder, which may be wired to a
VFD. The encoder data may be read by the PLC via the Controlnet
connection to the PLC.
[0098] In certain embodiments, for example retrofit application,
the status of all the I/O on the control system may be displayed on
the existing HMI and, to the extent possible, the appearance and
functionality of all icons and operator interactions may be
unchanged from the existing system. Certain functions and
instruments on the hydraulic distributor may also be added to the
HMI displays. The HMI thereby displays the status of all the I/O
devices associated with the hydraulic distributor. Alternatively,
in new installations a new HMI may be provided that includes all of
the necessary I/O devices associated with the hydraulic
distributor.
[0099] A proximity switch assembly 148 (See e.g., FIG. 3) may be
provided and used by the PLC to indicate home position for chute
rotation. The home position is when the distribution chute 102 is
lined up with the chute change door 56. See FIGS. 2, 3 and 7.
[0100] Also, embodiments of the distribution chute may include an
improved cradle design to allow the chute to be exchanged without
having to open the hydraulic distributor doors or enter the
hydraulic distributor case. In such embodiments, the chute change
door 56 on the blast furnace 10 is the only portal opening required
to exchange the chute 102 (see FIG. 2). Preferably, there are not
any pins to pull as this distribution chute 102 is designed to
simply insert into a cradle 103. As the chute 102 is tilted into
its rest position in the cradle 103, it may be locked into
position.
[0101] Tilt lock-out pins 172 may be provided for locking out tilt
function during maintenance (see e.g., FIGS. 4, 5, 8 and 11). The
lock pins 172 may include a flange connected to the hydraulic
distributor shell 104 and pin though the inner ring 110 to prevent
tilt movement during maintenance. The hydraulic distributor 100 can
be pinned, for example, at a minimum distribution chute angle and a
maximum distribution chute angle. FIG. 11 shows the lock-out pins
172 in the unlocked position.
[0102] FIGS. 24A-24D show an exemplary chute exchange process and
chute counter weight jig 190. As shown in FIG. 24A, the chute
access door 56 may be removed, the chute 102 may be rotated to its
maximum angle. Jig 190 enters the furnace 10 through the chute
access door opening 57. As shown in FIG. 24B, the jig 190 may be
connected to the chute 102. FIG. 24C shows the jig 190 rotating the
chute 102 to release it from chute locking surfaces 192 and 194 of
cradle 103. One of the advantageous of this design is that there is
no need to open or access the hydraulic distributor 100. As shown
in FIG. 24D, the jig may continue to rotate the chute 102 to
horizontal and the chute 102 may be removed from the furnace 10
through the chute access door opening 57.
[0103] In some embodiments, the cooling system of the hydraulic
distributor is a simple once through water system--instead of
closed loop cooling which would increase the capital and operating
cost of the system. In some embodiments, such as the embodiment
illustrated in FIG. 25, the water cooling of the hydraulic system
may include a shower cooled system that has water coverage on every
internal portion of the distributor that may conduct heat from the
blast furnace. The hydraulic distributor has a small rotational
mass to support the distribution chute and an external trough ring
that is stationary which also has refractory insulation. This
portion is not subject to vibration due to the rotation of the
chute. The refractory in this area is very stable and has a long
life.
[0104] In the illustrated embodiment, the hydraulic distributor
includes four 2'' water inlet pipes 108a. These pipes connect to an
enclosed trough located inside the top cover 106. The trough
discharges into a shower ring-pipe below the trough. The internal
shower ring-pipe has holes in it which are positioned to directly
spray the cooling water onto the feeder spout bushing. The water
cascades down the feeder spout bushing and onto the top of the
trunnion 120. The water collects in a shallow pool on top of the
trunnion horizontal surface. The water then overflows a weir wall
to cascade down the trunnion's vertical surface and is collected in
a trough located at the bottom of the hydraulic distributor shell
104. Once in the bottom trough, two paddles connected to the
rotating trunnion continually rotate to keep the water stirred up
and prevent settlement from falling out of the water and building
an insulating layer of debris in the bottom of the hydraulic
distributor. Further, in order to provide additional heat
protection to the hydraulic distributor, refractory may be applied
to all surfaces exposed to the inside of the blast furnace.
[0105] In some embodiments, nitrogen may be injected at a regulated
pressure into the hydraulic distributor housing at, for example,
two nitrogen inlet ports 108c (See e.g., FIG. 4) located
180.degree. apart, to provide a pressure that is higher than the
blast furnace top pressure. This positive pressure prevents dirty
blast furnace gas from entering the hydraulic distributor unit.
[0106] In an emergency situation, such as loss of cooling water,
the nitrogen regulating valve may open to allow nitrogen (e.g.,
about 1500-2000 SCFM of nitrogen) into the hydraulic distributor
for emergency cooling. In an exemplary embodiment, one of the two
inlets may be reversed to become an exhaust to prevent pressure
from building too high in the hydraulic distributor shell. This
emergency cooling is only intended to provide short term cooling to
protect the hydraulic distributor.
[0107] Preferably, redundancy is provided for both the tilt and
rotation motions. For example, multiple hydraulic cylinders may be
provided in some embodiments of the hydraulic distributor such that
the distribution chute tilt is able to continue to operate even if
one of the multiple hydraulic cylinders fails. Also, embodiments of
the hydraulic distributor may be designed such that a cylinder can
be easily replaced. For example, the cylinder may be mounted
outside the hydraulic distributor housing. In addition, embodiments
of the hydraulic distributor may include distribution chute
rotation redundancy by featuring a complete spare drive assembly
which may be, for example, mounted on the top cover plate 180
degrees away from the other rotation drive on the outside of the
hydraulic distributor housing. Further, the rotation drives may be
designed with an eccentric mounting flange. This design allows for
a quick change over from the primary to the backup drive.
[0108] The hydraulic distributor according to embodiments of the
present invention is built using substantially all fabrication
techniques--as opposed to casting techniques. Further, the
hydraulic distributor according to embodiments of the present
invention may be standard (e.g., standard size and dimensions) so
that it may replace a conventional gearbox (e.g., a PW
electro/mechanical gearbox). The standardized hydraulic distributor
may be set in the identical same location as a conventional gearbox
it is replacing without requiring any modifications to it or the
furnace. This provides an improvement over conventional designs
that were custom built to a particular furnace or application. A
standard hydraulic distributor results in ease of installation,
reduced down time, and cost savings when replacing a gearbox.
[0109] In addition, a standard hydraulic distributor having
substantially the same dimensions as the gearbox it is replacing
will also result in the distribution chute distributing burden
material exactly the same and in the same locations as the gear box
it is replacing. This may have a big impact on costs. The reason
for this is that each blast furnace has a specific burden
distribution model. A burden distribution model controls the
distribution of burden material so as to optimize and improve
performance. For example, burden distribution model dictates the
rotation and lift of the distribution chute to precisely locate
material within the furnace. If a hydraulic distributor is not
standard or the same as the gearbox it is replacing, then all the
burden distribution models have to be updated or new burden
distribution models must be generated. With a standard hydraulic
distributor that fits identically in the same location as the
gearbox it is replacing, the hydraulic distributor will distribute
material in the same location and the existing burden distribution
models may be used.
[0110] Chute rotation calibration may be accomplished as follows:
[0111] 1. With all alarms acknowledged or reset, the operator may
put the system into maintenance mode and then initiate the homing
operation. The operator should wait for the homing operation to
complete before attempting any other control actions. [0112] 2.
During homing, the following actions may occur: [0113] a) If not at
the home position, the chute will move toward the home position
switch at slow speed (set via the HMI). [0114] b) When the home
position switch is reached, the chute will stop, reverse direction
and then move off the home position switch until the first marker
pulse of the encoder is detected. [0115] c) This is the home
position. The system is now homed and ready for operation.
[0116] In some embodiments, the chute slope is mechanically limited
to a range of 3-55 degrees. The chute slope may be controlled by
the operator through the HMI. In the illustrated embodiment, there
are four hydraulic tilt cylinders that control the chute slope. The
hydraulic tilt cylinders extend to raise the chute and retract to
lower it. The hydraulic tilt cylinders may be controlled by a
hydraulic valve stand (described in more detail below), and the
position of each hydraulic tilt cylinder may be sensed by a
feedback device, such as a linear transmitter. The four linear
transmitters may generate an analog signal which may be an input to
the PLC of the control system. The position of each cylinder may be
displayed on the HMI. The chute slope may be determined by the PLC
based upon a calculation from the four linear transmitters.
[0117] Chute slope calibration may be accomplished as follows:
[0118] 1) The hydraulic tilt cylinders may extend until the chute
hits a mechanical stop. In some embodiments, the feedback devices
may read 55 degrees in the extended position. If the feedback
device output does not indicate 55 degrees, the feedback device
output may be re-calibrated to 55 degrees. [0119] 2) The hydraulic
tilt cylinders may retract until the chute hits a mechanical stop.
In some embodiments, the feedback devices may read 3 degrees in the
retracted position. If the feedback device output does not indicate
3 degrees, the feedback device output may be re-calibrated to 3
degrees. [0120] 3) If the feedback from one of the hydraulic tilt
cylinders is out of the allowable variance, the PLC may disregard
the signal from that device and an alarm may be set. If only two
units are in agreement then the chute position system is faulted
and the system should be inspected to determine the cause of the
mismatched outputs in order to prevent damage to the inner workings
of the hydraulic distributor.
[0121] The hydraulic tilt cylinders may be designed to have extra
stroke at both the min and max positions of the chute, e.g., 3
degrees and 55 degrees. Stop blocks (not shown) may be provided to
prevent the hydraulic tilt cylinders from being able to stroke past
the min and max degree positions. When the hydraulic tilt cylinders
stroke to the extreme positions, the inner ring, which the
hydraulic cylinders lift and lower, comes up against these stop
blocks. The purpose of this design is to make it quick and easy to
replace a hydraulic tilt cylinder. There is no need to spend time
shimming or adjusting the cylinder to get the chute at exactly 55
degrees when the cylinders are completely extended or at exactly 3
degrees when the cylinders are completely retracted since there is
extra stroke in the cylinders.
[0122] The PLC program may be zeroed as follows: [0123] 1. Retract
the cylinders until the inner ring comes up against the top set of
stop blocks. [0124] 2. Check that the chute is at 3 degrees. [0125]
3. Set the PLC program to a 0.000 stroke value, even though the
cylinder is at about 0.25-inch as explained above with respect to
extra stroke. The control system may then display that the chute is
at 3 degrees based on the 0.000 stroke value. [0126] 4. Extend the
cylinders until the inner ring comes up against the bottom set of
stop blocks. [0127] 5. Check to make sure the liner transducers are
reading approximately 12.3-inch, which the PLC may then calculate
the chute angle as being 55 degrees.
[0128] FIGS. 22A and 22B show piping assembly 190, which may be
used to control the chute slope position functions. As shown, the
assembly 190 may include appropriate piping, hoses, pressure sensor
and/or indicators. A remote hydraulic manifold, including pressure
reducers, filters, relief valves, solenoid valves, closed-loop
control network, reservoir, and the like, may supply a control
hydraulic fluid to the hydraulic tilt cylinders in order to cause
the cylinder rods to extend and retract. In one embodiment, the
system hydraulic pressure may be set to about 2500 psi.
[0129] The following lists basic operating data and parameters of
an exemplary hydraulic distributor:
TABLE-US-00001 minimum distribution chute angle 3.degree. maximum
distribution chute angle 55.degree. tilt cylinders (qty. 4) Bore-4
inch diameter (with cushion at both ends) Rod-2 inch diameter
Stroke-13.0 Inches hydraulic design pressure 3,000 PSI hydraulic
operating pressure 2,200 PSI hydraulic flow rate required 13 GPM
tilt angle change speed 3.degree. per second Rotation Speed 8 RPM
Rotation E-Motor 10 HP; 460 VAC; 60 Hz; 3-Phase
[0130] Although the invention has been described with reference to
exemplary embodiments, it is not limited thereto. Those skilled in
the art will appreciate that numerous changes and modifications may
be made to the preferred embodiments of the invention and that such
changes and modifications may be made without departing from the
true spirit of the invention. It is therefore intended that the
appended claims be construed to cover all such equivalent
variations as fall within the true spirit and scope of the
invention.
* * * * *