U.S. patent application number 10/817383 was filed with the patent office on 2005-10-06 for apparatus and method for controlling the amount of trash in lint.
Invention is credited to Gvili, Michael E., Lucus, Robert Lynn, Mezhebovsky, Stanisslav, Northern, Martin James.
Application Number | 20050217076 10/817383 |
Document ID | / |
Family ID | 35052609 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050217076 |
Kind Code |
A1 |
Gvili, Michael E. ; et
al. |
October 6, 2005 |
Apparatus and method for controlling the amount of trash in
lint
Abstract
An apparatus and algorithm for controlling the operation of a
lint cleaner in a cotton gin having motorized grid bars, in which
any one of the grid bars can be positioned in an engaged or
disengaged position. When the grid bar is in the engaged position
it functions as a lint cleaning instrument on a lint cleaning
machine. When it is in the disengaged position it does not
participate in the active cleaning process.
Inventors: |
Gvili, Michael E.; (Wayland,
MA) ; Mezhebovsky, Stanisslav; (Sudbury, MA) ;
Northern, Martin James; (Wolfforth, TX) ; Lucus,
Robert Lynn; (Lubbock, TX) |
Correspondence
Address: |
MIRICK O'CONNELL
MIRICK O'CONNELL, DEMALLIE & LOUGEE, LLP
1700 WEST PARK DRIVE
WESTBOROUGH
MA
01581-3941
US
|
Family ID: |
35052609 |
Appl. No.: |
10/817383 |
Filed: |
April 2, 2004 |
Current U.S.
Class: |
19/40 |
Current CPC
Class: |
D01B 1/04 20130101 |
Class at
Publication: |
019/040 |
International
Class: |
D01B 001/04 |
Claims
What is claimed is:
1. A variable rate lint cleaner for a cotton lint cleaning machine
with rotating saws, comprising: at least one grid bar with a
cleaning edge, and an actuator coupled to the grid bar, for moving
the grid bar between an engaged position in which the cleaning edge
is near the teeth of the saws and a disengaged position in which
the cleaning edge is farther from the saws.
2. The apparatus of claim 1, further comprising a driver for the
actuator, which on command sends signals to the actuator to move
the grid bar between the engaged and disengaged position.
3. The apparatus of claim 2, further comprising an operator
interface terminal which enables the use of said lint cleaner to
command the driver to position the grid bar into the engaged or
disengaged position.
4. The apparatus of claim 1, further comprising means for
activating the grid bar to a desired position.
5. The apparatus of claim 4, wherein the means for activating
comprises means for using an input trash level measurement to
determine the bars to engage with the lint.
6. The apparatus of claim 5, wherein the input trash level is
measured using imaging means.
7. The apparatus of claim 6, wherein the means for activating
further comprises a lookup table that is employed in response to
the input trash level.
8. The apparatus of claim 7 wherein the means for activating
further comprises using an output trash level measurement to
determine the bars to engage with the lint.
9. The apparatus of claim 8, wherein the output trash level is
measured using imaging means.
10. The apparatus of claim 9, wherein the means for activating
further comprises a lookup table that is employed in response to at
least the output trash level.
11. The apparatus of claim 1, further comprising a lint retaining
member coupled to the grid bar.
12. The apparatus of claim 1, further comprising a lint retaining
brush coupled to the grid bar.
13. The apparatus of claim 1, further comprising a movement
limiting stop for the grid bar.
14. The apparatus of claim 1, further comprising a stop switch for
the grid bar.
15. The apparatus of claim 1 comprising more than one lint cleaner
in series and at least one bypass valve used to bypass one or more
of the lint cleaners to reduce the amount of lint lost in the
cleaning process.
16. The apparatus of claim 1, wherein the actuator is responsive to
an input trash level, an output trash level, and a desired output
trash level.
17. An apparatus for a variable rate lint cleaner used in cotton
gins comprised of: at least one lint cleaning machine with rotating
saws and at least one grid bar, an actuator coupled to the grid
bar, for moving the grid bar such that its cleaning edge is either
in the engaged position near the teeth of the saws or disengaged
from cleaning operation such that its cleaning edge is moved away
from the teeth of the saws, a driver for the actuator which on
command sends signals to the actuator to move the grid bar to the
engaged or to disengaged position, and an operator interface
terminal which enables a user of said lint cleaner to command the
driver to position the grid bar into the engaged or disengaged
position.
18. The apparatus of claim 17, further comprising means for
activating the grid bar to a desired position.
19. The apparatus of claim 18, wherein the means for activating
comprises means for using an input trash level measurement to
determine the bars to engage with the lint.
20. The apparatus of claim 19, wherein the input trash level is
measured using imaging means.
21. The apparatus of claim 20, wherein the means for activating
further comprises a lookup table that is employed in response to
the input trash level.
22. The apparatus of claim 21 wherein the means for activating
further comprises using an output trash level measurement to
determine the bars to engage with the lint.
23. The apparatus of claim 22, wherein the output trash level is
measured using imaging means.
24. The apparatus of claim 23, wherein the means for activating
further comprises a lookup table that is employed in response to at
least the output trash level.
25. The apparatus of claim 17, further comprising a lint retaining
member coupled to the grid bar.
26. The apparatus of claim 17, further comprising a lint retaining
brush coupled to the grid bar.
27. The apparatus of claim 17, further comprising a movement
limiting stop for the grid bar.
28. The apparatus of claim 17, further comprising a stop switch for
the grid bar.
29. The apparatus of claim 17 comprising more than one lint cleaner
in series and at least one bypass valve used to bypass one or more
of the lint cleaners to reduce the amount of lint lost in the
cleaning process.
30. The apparatus of claim 17, wherein the driver for the actuator
is responsive to an input trash level, an output trash level, and a
desired output trash level.
31. An apparatus for a variable rate lint cleaner used in cotton
gins comprised of: at least one lint cleaning machine with rotating
saws; and a plurality of grid bars for cleaning lint that is
carried by the saws, wherein the grid bars are movable between an
engaged position in which the cleaning edges of the bars are close
to the teeth of the saws so that they participate in cleaning the
lint, and a disengaged position in which the cleaning edges of the
bars are farther from the teeth of the saws, so that they do not
participate in cleaning the lint.
32. The apparatus of claim 31, further comprising means for
automatically moving the grid bars between the engaged and
disengaged positions.
33. The apparatus of claim 32, wherein the means for automatically
moving the grid bars is responsive to an input trash level, an
output trash level, and a desired output trash level.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the lint cleaning process and
machinery used in cotton processing facilities such as cotton gins.
The invention provides an apparatus and methods for controlling the
amount of cleaning performed during the lint cleaning process, thus
optimizing the cotton producer's income by reducing waste and
damage to the lint.
BACKGROUND OF THE INVENTION
[0002] Lint cleaning machines, used in cotton processing
facilities, employ stationary grid bars to remove trash, leaves and
other particles from the lint during the cleaning process, as
described in W. S. Anthony and William D. Mayfield; Cotton Ginners
Hand Book United States Department of Agriculture; Agricultural
Research Service Agricultural Handbook Number 503; Copyright
December 1994 . The lint cleaner uses a bank of circular saws to
propel a thin preconditioned layer of lint through the lint
cleaning machine. The lint fibers, which may contain leaf
fragments, seed fragments, sticks and other particles designated
herein as trash, are fed onto the fine teeth of the saws, which are
rotating at the speed of a few hundred revolutions per minute.
During one half of a revolution around the cleaner, the lint fibers
pass by a set of five or more closely positioned bars with sharp
edges, referred to as grid bars. These grid bars are positioned
perpendicular to the rotation of the saws, with the edges very
close to the saws. As the lint passes by the grid bars, most of the
trash in the lint is dislodged by the grid bars and sucked into a
trash air pipe, which then feeds the trash to a trash heap outside
the gin house. The saws continue pulling the lint through most of
the revolution. The lint is then separated from the saws by a
cylindrical brush and from there is conveyed to a bale press for
packing. The bale press packages the lint into 500 pounds bundles
of pressed lint called bales.
[0003] The grid bars are long metal bars with a sharp leading edge
used to remove the trash from the lint upon contact. It has been
demonstrated that during the cleaning process the grid bars also
remove some usable lint from the rotating saws, causing a loss of
lint to the producer. It has been further determined that the
amount of trash and lint removed during the cleaning process is
dependent on many factors. These include the mechanical positioning
of the grid bars, the sharpness of the cleaning edge, the condition
of the lint, the lint properties, the mechanical properties of the
saws, their speed and other factors. It has been demonstrated that
the loss of useable lint can decreased by reducing the amount of
cleaning the machine performs. It has also been demonstrated that
reducing the amount of cleaning results in longer fibers and
reduction in short fibers. Reduction in the lint cleaning thus
results in the improvement of the quality of the cotton. In many
situations, the cotton producer is interested in minimizing the
loss of lint during the cleaning process, even if it will result in
higher trash content. Existing lint cleaners do not provide a
method to vary the amount of cleaning the machine performs.
[0004] U.S. Pat. No. 5,909,786 by Anthony, describes an apparatus
to reduce fiber waste by lint cleaners. Anthony's invention
describes a method where the space between the grid bars is closed
by shroud members, while the grid bars themselves remain stationary
during the cleaning process. The disadvantage of Anthony's
invention is that it does not remove sheet metal edges from
contacting the lint, thus continuing to cause damage to the fibers.
Also, Anthony's invention is complex to build and operate.
[0005] Some trash particles are not removed by the lint cleaner.
They remain with the lint through out the remainder of the cleaning
process. The amount of trash remaining in the lint will be measured
as a leaf count. The leaf count is one of the parameters used to
determine the quality of the lint.
SUMMARY OF THE INVENTION
[0006] An apparatus and algorithm for controlling the operation of
a lint cleaner in a cotton gin having motorized grid bars, in which
any one of the grid bars can be positioned in an engaged or
disengaged position. When the grid bar is in the engaged position
it functions as a lint cleaning instrument on a lint cleaning
machine. When it is in the disengaged position it does not
participate in the active cleaning process. The grid bars can be
engaged or disengaged in the cleaning operation by electrical,
pneumatic or hydraulic actuators, which are activated by the system
processor. The operator interface device, which contains at least a
trash level indicator and a data entry device, allows the operator
to enter the desired cotton gin output trash level. An imaging
device, such as a digital camera or a scanner, measures the amount
of trash present in the lint before cleaning plus another imaging
device, like a digital camera or a scanner, measures the amount of
trash remaining in the lint at the cotton gin output after the lint
cleaning process. The signal received from the imaging devices is
analyzed and the trash content is determined. The invention
algorithm determines which grid bars should be engaged in the
cleaning process to obtain the operator's desired output trash
content. An alternate algorithm can be used to calculate the most
cost effective cleaning process based on commodity pricing, trash
discount or quantity of lint wasted.
[0007] This invention further comprises an automatic control for
lint cleaning machines where the cleanliness of the lint is
monitored by an imaging device such as a camera or scanner, and an
assembly of motorized bars. The motorized grid bars are dynamically
configured by the invention's algorithm to produce the desired
level of cleaning.
[0008] The inventive system is represented in FIG. 1, but is not
limited to the components of FIG. 1. It consists of an imaging
device which can estimate the amount of trash existing in the lint
before it enters the lint cleaner, and a second imaging device at
the exit point of the lint cleaner or at the final station when the
bat is packaged into a bale of cotton. An estimate of the amount of
trash in the cotton during process is calculated continuously;
several times for each bale. The results are then averaged to
obtain a moment by moment condition of cleanliness before and after
the cotton is cleaned. This occurs in a timely fashion so the lint
cleaner process algorithm can be performed. This invention also
includes movable grid bars, typically either movable by hand, or by
the use of motors, which may be manually or automatically
controlled to engage and disengage one or more grid bars. These
grid bars are equipped with electrical motors, or pneumatic or
hydraulic actuators, or other remotely controlled actuators,
referred to here as grid bar actuators. The actuators enable the
invention's lint cleaner controller to position the grid bars
against the rotating battery of saws, referred to herein as the
engaged position, or to separate them so they do not take part in
the cleaning process, referred here as the disengaged position.
While the grid bar is in the engaged position it is functioning as
a trash-removing surface which removes trash from the cotton being
cleaned. Any one of the grid bars can be independently repositioned
by the actuators, at any moment during the cleaning process. A grid
bar can be moved to the disengaged position where the surface of
its cleaning edge is no longer in contact with the lint or the
trash. In this position, the grid bar is not being used as cleaning
device, and in that position it no longer cause any loss of lint or
damage to it.
[0009] The grid bars may also be equipped with a lint-retaining
member such as retention bars or retention brushes or both, as
shown in FIGS. 6 and 7. Both the retention bar and the retention
brush keep the lint in contact with the saws when the grid bar is
in the disengaged position. The retention bar or brush prevents the
possibility of dislodging the lint from the saw by the fast flowing
air. The dislodging of lint from the saws is due to the centrifugal
forces applied by the spinning of the saws.
[0010] This invention also includes a user interface terminal where
the operator has the ability to set the desired output trash level,
and also to adjust other system parameters. They can also view the
condition of the cleaning process in regards to the position of
each of the grid bars. The operator can reposition the grid bars in
a manual mode by commanding the processor to engage or disengage
any selected grid bar at any time.
[0011] This invention includes a processor, which executes a
sequence of commands, embedded in its memory, constituting the
algorithm of the invention. The processor receives inputs from the
optical sensing devices, it also receive instructions and or set
point from the operator. It uses these inputs to determine if it is
necessary for one or more of the grid bars to be repositioned to
the engaged or disengaged position. If there is a need the
processor can use these inputs to tell which of the grid bars need
repositioning.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a diagram of one embodiment of the invention,
having a lint cleaner with movable grid bars.
[0013] FIG. 2 is a system diagram of one embodiment of a lint
cleaning, control and monitoring system of the invention.
[0014] FIG. 3 is a diagram of one embodiment of motorized grid bars
mounted on a lint cleaner according to the invention.
[0015] FIG. 4 is a diagram of an alternative motorized grid bar
using worm gear.
[0016] FIG. 4a is a diagram of another alternative motorized grid
bar using a solenoid type of actuator for the grid bars of the
invention.
[0017] FIG. 5 is a diagram of another alternative pneumatic or
hydraulic type actuators for the grid bars of the invention.
[0018] FIG. 6 is a diagram of a grid bar of the invention, which is
moved along an arched and linear positioning groove.
[0019] FIG. 6a is a diagram of an inventive grid bar, with a solid
lint retention member.
[0020] FIG. 7 is a diagram of another inventive grid bar, with a
lint retaining brush.
[0021] FIG. 8 is a diagram of a closed control loop for an
embodiment of the invention.
[0022] FIG. 9 is a block diagram of another control scheme
according to the invention.
[0023] FIG. 10 is a schematic diagram of a three-way valve used to
bypass a second lint cleaner, illustrating another feature of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The invention of lint cleaning machine in a cotton
processing facility such as cotton gin, is illustrated in FIG. 1.
The lint cleaner is comprised of a battery of saws 1 containing
multiple, round, narrow saws of the typical diameter ranging from
16 to 24 inches. All of the saws are spinning around the same axis
2 and driven by a single motor or mechanical drive or gear 3
through the shaft or belt 4. The motor or gear 3 is mounted on a
stationary frame 5 of the lint cleaner, which also supports the
housing and other components of the lint cleaner 6. On the frame 5
are several mounted grid bars 7 and 8 as shown in FIG. 1. The
invention applies to the use of one or more grid bars in a lint
cleaning machine. Each of the grid bars is mounted on a pivoting
shaft 9 and 10. Electric motors 11, 12, 13 and 14, such as step
motor with or without a gear, rotary solenoids or other actuators
are coupled to the shafts, to controllably rotate the shafts. These
grid bars are mounted respectively on ribs 15 of the frame 5 and
are coupled to the shafts of the corresponding grid bars as shown.
This allows a fine control of the rotation and angle of the grid
bars during the operation of the lint cleaning process. The motors
are fed electrical power and electrical signals, via power and
signal cables 17. The motors 11, 12, 13 and 14 can rotate the
respective grid bars to the desired angle in relation to the
spinning saws 1.
[0025] As part of this invention shown in FIG. 2, a layer of lint
16 is fed into a lint cleaning machine 5. An input imaging device
70 is capturing images of the incoming lint and transferring them
to the signal processor 69 for trash level evaluation. The lint
cleaning machine 5 consists of at least a battery of rotating saws
1 and a multiplicity of the inventive motorized grid bars 7 with
actuators 11 and 12, and the motorized grid bar 8 with actuators 13
and 14. Trash 27 and residual lint fibers 28 are removed from the
lint 16 by the grid bars 7 and 8. The clean lint is fed from the
lint cleaning machine into a condenser and from there to a lint
slide where the output imaging device 73 is taking images of the
lint after the lint cleaning process and transferring the images to
the output image processor 69A. The output image processor
evaluates the images and calculates the amount of leaves and trash
27 remaining with the lint. That information is fed into the system
processor for final determination of the grid bars deployment. The
system processor uses the inventive algorithm to determine what
shall be the grid bar deployment at that moment based on the leaf
and trash contents at the input and the output of the cleaners, and
the desired output leaf count as fed to it by the operator using
the operator terminal 66. The deployment is executed by the
motorized grid bar driver 18 which sends the needed electrical
signal to the grid bar actuators.
[0026] As shown in FIG. 3, when grid bar 7 is rotated to a
reference angle 24, it will be in a position where its sharp
cleaning edge 25 is near the edge of the teeth 26 of the spinning
saw 1. This distance typically ranges from 30 to 60 thousandths of
an inch, thus it will be participating in the cleaning process.
This position is defined as the engaged position when the grid bar
is engaged in the cleaning process. Trash particles 27 which are
attached to the lint at the beginning of the process, may be
removed and separated from the lint as it hits the cleaning edge of
the grid bar 27. During the operation, some usable lint 28 will
also be separated from the lint 16 which is spun by the saws 1. Not
all the trash particles are removed by the first grid bar 7. Some
trash particles will be removed by subsequent grid bars which are
in the engaged position. Grid bars which are in the disengaged
position, such as grid bar 8 as illustrated in FIG. 3, will not
have their sharp cleaning edge 25 near the teeth of the spinning
saws. This means they will neither perform any cleaning function,
nor cause a loss of usable lint. The distance between the cleaning
edge of a disengaged grid bar to the tip of the teeth of the
spinning saws typically ranges from 0.25 to 0.5 inches, or greater.
This way the spinning lint held by the teeth of the saw will not be
in contact with the sharp cleaning edge of the grid bar and
therefore, will not be affected by it. The disengaged grid bar will
be set at the rotational angle 31, which is greater than angle 24.
As part of this invention, the motors attached to each of the grid
bars will manipulate the bar's respective angular position in
relation to the saws, positioning them in an engaged position or in
a disengaged position. Fine control is used to adjust the distance
of the edge from the saws in the engaged position, to finely adjust
the amount of trash removed by that bar and to prevent the bars
from incidentally touching the saws. The movement of the grid bars
is performed at a special slow motion to prevent the flexing or
vibration of the bar thus reducing the possibility of the bars
touching the saws; an event which may cause sparks and fire in the
gin. It should be mentioned that some trash particles 27 will stay
with the lint in the process, and miss the cleaning edges of all of
the engaged grid bars and will continue to remain with the lint to
its final packing stage.
[0027] Part of this invention is the design of the grid bar motors
and actuators as illustrated in FIGS. 4, 4a and 5. Shown in FIG. 4
is inventive grid bar 7, which is movable via a worm gear assembly.
The worm gear assembly contains a toothed wheel 34, a cork screw
pin 35, a pivot pin 36, and a shim 37. Stepper motor 38 is
connected to the controller via electrical cable 39. The stepper
motor is also equipped with an encoder, which enables it to verify
the number of revolutions the motor rotates. The invention's
motorized grid bar is used to engage and disengage the sharp
cleaning edge 25 from the lint in process 16. As the cork screw pin
35 is rotated counter clockwise by the stepper motor 38, it causes
the toothed wheel 34 to turn in a clockwise direction. This also
rotates the grid bar clockwise since the two are locked together by
the shim 37 and turn together on the pin 36. As a result, the grid
bar cleaning edge will separate from the saw teeth and from the
lint and will no longer take part in active cleaning of the lint
16. This separation will also not cause loss of useable lint. When
the stepper motor 38 turns the corkscrew 35 in the clockwise
direction the grid bar will return to the engaged cleaning
position. The angle of the turn must be accurate so that the grid
bar will not come to rest too close to the edge of the saw teeth or
come in contact with the saw's teeth. This could cause damage or
even a fire. An encoder built into the stepper motor helps
determine the number of revolutions the corkscrew makes. From this
information the turning angle of the grid bar can be calculated
using linear the equation (1). A stop wedge 43 and a stop switch 45
can also help prevent the grid bar from over rotation. As the grid
bar rotates to the engaged position, it come to a stop against the
stop wedge 43. The wedge stops the rotation of the grid bar by
pushing against a step 44 on the edge of the grid bar when it comes
to its final resting angle. The step 44 is built into both grid bar
edges. The stop wedge 43 is attached to the frame 5 of the machine.
The stop switch 45 provides a closed contact signal to the
processor via cable 46 when the grid bar reaches it final engaged
position. It can be used by the processor to determine when to stop
the rotation of the grid bar.
[0028] The angle of rotation .iota. of the grid bar 7 is calculated
in the following equation (1):
.iota.=(w/360)*360/N (1)
[0029] where N is the number of teeth on the gear 34, and w is the
rotation angle of the step motor 38.
[0030] The tangent distance of travel for the cleaning edge 25 is R
times the angle of rotation in radians, when R is the distance of
the cleaning edge from center of rotation.
[0031] FIG. 4a shows another alternative actuator for engaging and
disengaging the grid bar in and out of the cleaning process. Shown
in FIG. 4a is a solenoid 48 with its current driving supply cable
49, and an anchor pin 50 which holds the stationary part of the
solenoid fixed to the lint cleaning machinery frame 5, and the
plunger 52 which is anchored to the tail of the grid bar 7. There
are types of solenoids which operate both forwards and backwards,
allowing them to engage or disengage the grid bar by applying the
correct electrical signal. Alternatively, a spring 53 can be used
to retract the grid bar to its disengaged position. When the
solenoid is activated by the application of voltage, it applies
pulling force greater then that of the spring, thus bringing the
grid bar closer to the saws into the engaged position. When the
solenoid is deactivated it releases the grid bar and allows the
spring to pull the grid bar away from the saw to the disengaged
position. The spring 53 is anchored at one side on the frame 5, and
on its other side to a pin on the side of the grid bar 7. The
preferred method in which the solenoid 48 is activated, is the
application of a pulse width modulated signal. Starting to apply
power to the solenoid with a low duty cycle will generate a
relatively small force. Gradually, the processor increases the duty
cycle to its full one hundred percent for full force application.
Gradual application of the solenoid force prevents a sudden
movement of the grid bar, thus preventing it from flexing and
incidentally touching the saws 1.
[0032] FIG. 5 illustrates another alternative method for engaging
and disengaging the grid bars. It utilizes pneumatic or hydraulic
cylinders to perform the motion. As illustrated in FIG. 5, a
pneumatic cylinder 54 is pinned to the grid bar 7 at its extendable
rod 55 using a pin 56. The other end of the cylinder is attached to
the frame 5 of the lint cleaner. Two pressurized air or oil
carrying pipes 56 and 57 feed into the inside pressure chamber of
the cylinder and provide the required force to move the extendable
rod 55 in the desired direction. A bar stop structure such as
described above may be used with any embodiment of the
invention.
[0033] FIG. 6 and 6a illustrate the lateral movement of the grid
bar along arched and linear positioning grooves according to an
aspect of the invention. As part of this invention, the grid bar 7
can be fitted with at least two guiding pins 58 and 59 which extend
beyond the sides of the grid bar. These are inserted into guiding
grooves 60 which are accomplished in the frame 5 of the lint
cleaner. The grooves can be straight or curved. When the grid bar
is forced to move to the engaged position, the grooves lead it to
that position, stopping it at a desired distance from the teeth of
the saws, as the pins reach the end of the grooves. The curved
groove 60 can also be designed to position a lint retaining member
61, which is part of the grid bar and extends along the entire
length of the grid bar against the teeth of the saw when the grid
bar is in the disengaged position. This lint retaining member has a
surface that helps to keep the lint in process closely attached to
the saws, reducing the possibility of having any lint dislodged and
removed during the lint cleaning process by subsequent grid bars'
cleaning edges or by the air flow 47 around the saws. Grid bar 7 in
FIG. 6 is shown in the disengaged position where the lint retaining
member is in close vicinity to the saws. Trash is not removed from
the lint in this process and no lint is wasted when removed by the
grid bars.
[0034] The position of the grid bar in FIG. 6a is in the engaged
position, pushed forward to the front end of the grooves.
[0035] FIG. 6 shows the grid bar 7 with a lint retaining member 61
of the invention attached. The retaining member is designed to hold
the lint being spun by the saw 1, attached to the teeth of the
saws. This prevents the lint from being removed from the saws and
discarded as trash. The lint retaining member 61 is part of or
attached to the bottom side of the grid bar, extending from side to
side. It has a smooth, curved surface 63 which prevents the
dislodging of lint pieces 28 from the saw 1. The retaining member
pushes the lint closer to the teeth of the saws. The retaining
member can be an integral part of the grid bar or an attached piece
held together with fasteners 62. It can also be inserted into a
groove 33 built into the body of the grid bar. The shape of the
retaining bar is design to provide maximum retaining member area in
proximity to the saw while maintaining safe distance from the teeth
of the saws. The material of the retaining bar is non metallic,
such that in the event of incidental impact with the saws, the
retaining bar will not cause a spark but be chipped off.
[0036] FIG. 7 shows details of a brush type of the lint retaining
member, attached to the grid bar 7. At least one row of bristles 64
on the brush 65 are attached to the bottom of the grid bar at an
angle to its bottom surface. The edge of the brush is positioned
close to the rotating saws 1. When the grid bar is in the engaged
position the bristles of the brush 64 do not touch the teeth of the
saw. When the grid bar is in the disengaged position as shown in
FIG. 7, the bristles of the brush do reach the tip of the saws 42
which gently align the lint to the saw's teeth. This keeps the lint
flowing over the saws. The brushes on the grid bars are built along
the entire length of the grid bar so they reach the entire length
of the battery of saws. FIG. 7 also shows the mechanics of a
manually operated grid bar. A spring 90 is attached to a pin 91 on
the grid bar 7 and to a stationary pin 92 on the body of the lint
cleaner 5. The pin 91 is positioned on the side of the grid bar,
approximately half way from the tip 25 to the pivot point 93. The
stationary pin 92 is attached to the body 5 on the opposite side to
the pin 91 in relation to pivot 93 so that when the grid bar is in
the engaged position the spring will hold the grid bar 7 against
the bottom stop wedge 43, and when the grid bar is in the
disengaged position the spring will swing the grid bar away from
the saws to that position, as shown in FIG. 7, and hold it steady
against the upper stop wedge 95. A handle 96 can be used to swing
the grid bars from one position to another manually. The handle
will be coupled to the grid bar at its base near or at its pivot
point 93, and can be removed when not in used.
[0037] FIG. 8 illustrates the variable rate lint cleaning signal
flow diagram. The system in this configuration consists of an
operator trash set point entry device 66, a grid bar processor 75,
an imaging device 70, an image processor 69, and a grid bar driver
76. Also shown in FIG. 8 is the lint before cleaning 16, the lint
cleaner saws 1, and a grid bar 11. The operator, using his
interface terminal 66, enters a desired output trash level Ts,
which is fed into the first input port of the grid bar processor
75. This entry represents the desired amount of trash at the end of
the cleaning process. The trash level can be presented as a leaf
count figure, or other relative number such as a percent of trash.
The imaging device 70 captures images of the lint before cleaning
16, and sends them to an image processor 69 for trash level
analysis, which is known in the art. The resulting incoming trash
level, Ti, is fed into the second port of the grid bar processor
75. This figure, the incoming trash level, Ti, can be a leaf count
figure or any other relative number such as the percent of trash.
The desired output trash level, Ts, and the incoming trash level,
Ti, are two input signals used by the grid bar processor 75 to
calculate the number of grid bars to be deployed in the lint
cleaner. The grid bar processor uses a lookup table such as Table A
to determine the number of grid bars needed to clean the incoming
lint to the desired level. If no other imaging devices are
installed, this calculation will determine the final number of grid
bars to be engaged in the cleaning process. Using Table A one can
determine the number of grid bars needed to clean the lint to the
desired output trash level. The number of grid bars needed to be
engaged are determined by crossing the line of current incoming
trash level Ti with the column of the set trash level Ts. The
processor activates the grid bars to their engaged or disengaged
position starting with grid bar number one, at the top of the lint
cleaner such that the grid bars in the engaged position will be
consecutive. The outcome of the grid bar processor 75 is fed into
the grid bar driver 76 which, in turn, sends the appropriate
signals to the grid bars' actuators to move them to the proper
engaged or disengaged positions.
[0038] Grid bar deployment Table A, or similar, is constructed
experimentally in a cotton gin of similar lint cleaner properties
as that of the gin where the system and the table is to be
utilized. While the gin is operating at a given steady, not varying
significantly, input trash level, the operator deploys any number
of grid bars combination possible such as one grid bar, two grid
bars, three grid bars, etc., at a time, and records the output
trash level obtained as the result of each combination. He enters
the results into a table of the sort designated as Table A where
the columns designated as Desired Output Trash Level (Ts) represent
the actual trash level achieved. The operator repeats the procedure
for different input trash levels so it covers all the expected
range of trash levels expected to be fed into the gin.
1TABLE A Grid bar deployment schedule Input Trash Desired Output
Trash Level (Ts) Level Ti 1 2 3 4 5 6 7 8 1 0 0 0 0 0 0 0 0 2 2 0 0
0 0 0 0 0 3 4 1 0 0 0 0 0 0 4 6 3 1 0 0 0 0 0 5 8 5 3 1 0 0 0 0 6
10 7 5 3 1 0 0 0 7 12 9 7 6 3 2 0 0 8 14 11 9 8 7 6 5 0
[0039] FIG. 9 illustrates the variable rate lint cleaning signal
flow diagram with two imaging devices, one at the lint cleaner
input before cleaning and one at the lint cleaner output after
cleaning. The system in this configuration consists of an operator
trash set point entry device 66, a grid bar processor 75, a
secondary grid bar processor 77, an input imaging device 70, an
output imaging device 73, an input imaging processor 69, an output
imaging processor 74, and a grid bar driver 76. The front end
portion of this system configuration operates similarly to the one
described in FIG. 8. The desired output trash level Ts is fed into
a port of the Grid bar processor 75. The incoming trash level
signal from the input imaging device 70 is fed to the input image
processor 69 and from there is fed into the second port of the grid
bar processor 75. The grid bar processor 75 calculates the
deployment schedule using Table A and feed the results into the
first port 78 of the secondary grid bar processor 77. The trash set
point signal is also fed into the secondary grid bar processor 77
via its port 80. The output trash level To, which is obtained from
the images taken by the output imaging device 73 and calculated by
output imaging processor 74 is also fed into the secondary grid bar
processor 77 via its third port 79. The secondary grid bar
processor 77 then calculates the final grid bar deployment
schedule, using it three input signals and the grid bar deployment
correction Table B. The grid bar deployment schedule is sent to the
grid bar driver 76 which in turn drives the actuators of the grid
bars to the correct engaged or disengaged positions.
[0040] In order to reduce the number of alteration the grid bars
undertake, the grid bar processors 75 and 77 utilize a rolling
averaging formula (2) which outputs the results once every user
selectable output deployment time interval.
GB(Drive)=int(a0*GB(t)+a1*GB(t-1)+ . . . +ai*GB(t-2)+ . . .
an*GB(t-n)+a) (2)
[0041] Where:
[0042] GB(Drive) is the averaged grid bar deployment figure to be
output to grid bar driver,
[0043] GB(t) is the grid bar deployment figure from the current
calculation cycle,
[0044] GB(t-1) is the grid bar deployment figure from the previous
calculation cycle,
[0045] . . .
[0046] GB(t-n) is the grid bar deployment figure from the nth
previous calculation cycle
[0047] a0 through an are coefficients of weight which can be
adjusted to increase or decrease the affect of the averaging. a0
through an are smaller then 1 and greater or equal to 0 except of
a0 which should always be greater then 0. The sum of the
coefficients a0 through an should be equal to 1. a is a constant
used to round up to the nearest integer; 0<a<1.
[0048] The number and coefficients ai can be chosen to be any
number greater then 1. at least a0 should be greater than 0. The
number and the value is determined based on the stability and
responsiveness of the system during operation. When the final grid
bar deployment figure GB(Drive) is varying too often then the
system shall include more coefficients, averaging the calculation
over longer sequence of grid bar deployment figures. When greater
responsiveness is required due to fast changing conditions of the
lint, a smaller number of coefficients should be used, but more
than 0, so the average will be of shorter history.
[0049] Grid bar deployment Table B is constructed experimentally in
a cotton gin of similar lint cleaner properties as that of the gin
where the system and the table is to be utilized. While the gin is
operating at a given steady, not varying significantly, input trash
level, the operator records the trash removal error defined as
Ts-To and then he engages or disengages one or more grid bars to
bring this error to zero or close to it within half of a point. The
proper correction is then recorded in the corresponding column on
the same line. It should be noted that at different input trash
levels there may be different corrections to grid bar schedule thus
requiring the creation of multiple tables of type B, one for each
level of input trash level.
2TABLE B Grid bar deployment correction schedule. Correction to
number of grid bars Difference between to be engaged (positive
number = set point and out trash bars to engage Negative (Ts - To)
number = bars to disengage) -1.5 2 -1.0 1 -0.5 1 0 0 0.5 -1 1.0 -1
1.5 -2
[0050] Since most gins require two or more lint cleaners in order
to clean the lint to the commonly specified level, the system
described in this invention can utilize three way flow valves to
route the lint through multiple cleaners, or bypass any one or more
of them, in any desired order. Illustrated in FIG. 10, with a use
of a valve 81, the gin operator can operate only one lint cleaner
88 with motorized grid bars 11, yet have complete flexibility as to
the number of grid bars he engages. Using one or more lint valves
81, any number of grid bars from one to m* n can be engaged in the
cleaning process. Where n is the inherent number of grid bars
contained in a single lint cleaner of the type being used in the
facility, and m is the number of lint cleaners used in the
facility. FIG. 10 shows two lint cleaners, standard lint cleaner 86
with four stationary grid bars 87, and the inventive lint cleaner
88 with four motorized grid bars 11 (only one shown). The lint
cleaners are connected via a three-way valve 81. The three-way
valve has a motorized gate 82 which can direct the lint from its
input 83 port to either the primary output port 84 or the secondary
output port 85. Thus when fewer then four grid bars are needed to
clean the lint to the desired level of cleanliness, the ginner can
flip the gate 82 down so the lint will bypass the second lint
cleaner 86, thus unnecessary loss of lint is eliminated.
[0051] As part of this invention, the trash image processors 69 and
72 calculate the amount of trash present in the lint. The image
must be clipped so it does not include area which is not fully
covered by the lint. This can be determined by calculating the
amount of dark areas in different areas of the image. Portions
which contain dark spots in excess of 5% are suspected of being
poorly covered by the lint and should be excluded from the trash
estimation process. The images are converted to a black and white
image with the threshold set to 50 percent. This threshold level
can be adjusted permanently or dynamically for lighting variation
present during the taking of the images.
[0052] Table A provides the deployment schedule for grid bars. For
every input trash level, also known as input leaf count, and for
every output trash level, or leaf count, the operator can determine
the number of grid bars to be deployed by reading the cell in the
Table A which crosses the line and column of the corresponding
trash figures. The table itself can be generated empirically by
cleaning lint of different level of trash contents with the
different grid bar deployment, starting with one bar through the
entire set of grid bars in the cleaner, and measuring the effect in
every case.
[0053] Table B provides the deployment correction for the lint
cleaner's grid bars when an output imaging sensor is available to
measure the output trash contents. The table can be used in the
manual mode when the output leaf count figure is obtained from a
qualified inspector. The table can be used in automatic mode where
the output leaf count is fed to the grid bar processor 77 shown in
FIG. 9.
[0054] In the manual mode the operator can enter the output trash
contents, into the operator terminal 66. The data is then
transmitted to the grid bar processor 77 where the final grid bar
deployment correction is determined based on Table B.
[0055] In the automatic mode the output trash content is calculated
by the output image processor 74 and the result is transmitted to
the secondary grid bar processor 77. The processor uses Table B to
determine the correction to the grid bars deployment based on the
output trash level To and the desired trash level set by the
operator as a input set point Ts. The processor calculates the
difference Ts-To and determines the correction schedule according
to the number appearing in the right column of the Table B. A
positive number designates an increase in the number of grid bars
to be engaged, and a negative number designates a decrease in the
number of grid bars to be deployed. The result is sent to the grid
bar driver as the final deployment. It should be mentioned that
this correction determination based on Table B should be performed
after the initial deployment determined by Table A and the input
trash level content as executed by the first grid bar processor 75
of FIG. 9.
REFERENCES
[0056] [1] Anthony; U.S. Pat. No. 5,909,786 Apparatus and method
for reducing fiber waste.
[0057] [2] Mayfield et al.; Effects of Grid Bars On Lint Cleaners
Performance; The Cotton Gin and Oil Mill Press; Jun. 13, 1992.
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