Note: Descriptions are shown in the official language in which they were submitted.
CA 02410774 2002-12-04
INTRODUCTION
This invention relates to a rotary debarker ring which applies an adjustable
force to the
surface of a log, and more particularly, a rotary debarker ring which has a
self contained
remotely controllable and programmable mechanism for producing and
automatically
compensating the force with which bark is removed from a log in an out feed
manner.
BACKGROUND OF THE INVENTION
The operational function of this invention is the same as is known in the art,
in that logs
are feed through the central bore of the rotary debarker ring as the rotary
debarker ring is
rotated causing pivoting scrapers to remove the bark as the pivoting scrapers
contact the
log. Rotary debarker rings typically employ a number of pivoting scrapers each
of which
possess a pivotal axis and a scraping edge being parallel to the rotational
axis of the
rotary debarker ring, ranging from as few as three (3) to as many as six (6)
pivoting
scrapers. The pivoting scrapers contact a log in a trailing manner relative to
the rotary
debarker rings rotational direction, however the pivoting scrapers do not
contact a log in
a trailing manner relative to the log feed direction. The pivoting scrapers
are forced to
pivot inwardly so as to close or reduce the size of the opening produced by
the pivotal
position of the pivoting scraper's scraping edge, by means of the air
pressure. A log
being feed into a rotary debarker ring contacts the scrapers forcing the
pivoting scrapers
to pivot outwardly so as to open or increase the size of the opening produced
by the
pivotal position of the pivoting scraper's scraping edge. The contacting of
the log by
each scraping edge produces spiral-scraping paths due to the log feed
direction and the
rotary debarker rings rotational direction. To ensure that the bark is removed
an
overlapping of the scraping paths is produced by limiting the feed rate of the
log
proportionality to the rotational speed of the rotary debarker ring. The feed
rate of the
CA 02410774 2002-12-04
log is to be equal or less than the number of scraping edges multiplied by the
contact
Length of the scraping edge, multiplied by the number of revolutions of a
rotary debarker
ring in a given amount of time, for example, a rotary debarker ring consisting
of six (fi)
pivoting scrapers each of which possess scraping edges being three (3) inches
in length,
enable a feed rate of eighteen (18) inches per revolution of the rotary
debarker ring, thus
being rotated at a speed of two hundred revolutions per minute (200 R P M),
would
provide for a the maximum log feed rate of three hundred (300) feet per
minute. A
typical rotary debarker ring removes the bark from a log utilizing an in feed
debarking
process, which removes the bark from a log before the log passes through the
rotary
debarker ring. This has been the method of choice due to the limitations of
the
geometrical configuration being reduced or more favorable as applied to the in
feed
debarking process with regards to the accumulation of bark in the central bore
as well as
between the pivoting scrapers and the rotary debarker ring. A log entering a
rotary
debarker ring forces the pivoting scrapers to pivot such that an opening of
the pivoting
scrapers is produced relative to the scraping edges, when the leading end of a
log is
tapered enabling a much more smooth transitional movement relative to the
pivoting
scrapers pivotal, from a closed position to a open position, so as to enable
the debarking
of a log. However if the log end is large and virtually flat, as is commonly
produced by a
saw, the pivoting scrapers do not have the ability to open in a smooth
transitional manner
but are required to pivot very quickly as contact is made in a more abrupt
manner
occasionally resulting in damage to both the log and rotary debarker ring. The
ability to
compensate for the restrictive aspects of the geometrical limitations of the
configuration
of a rotary debarker ring as is known in the art is provided by various means
however the
required speed and accuracy relative to timing of this pivotal movement is
often the cause
of extensive damage. This geometrical configuration as is known in the art is
restricted
in several ways,
~ The limited maximum number of pivotal scrapers containable within a single
rotational path due to the intersecting pivotal paths and the economy of size.
This
restrictive aspect being, that as the pivoting scrapers axis is positioned
farther
away from the rotational axis of the rotary debarker ring in order to provide
the
additional space required for additional scrapers, a proportional decrease in
the
leverage aspect of the application of force to the surface to the log results,
requiring a proportional increase in the strength and space requirements of
the
components which provide the supporting aspects of the scraping edge, thus the
restrictive aspect of the maximum number of pivoting scrapers potentially
containable within a single rotary debarker ring while being rotated in a
single
rotational path.
~ The inability to ensure that the scrapers will not contact with each other
under
normal operating conditions resulting in damage. This restrictive aspect being
that the geometrical configuration limits the movement of the pivoting
scrapers
dynamically, under normal operating conditions, allowing a potential for the
pivoting scrapers to contact each other due to the intersecting pivotal paths.
The
scrapers are required to be moved in such a manner that all the scrapers are
pivoted in a range of unison. Each pivoting scraper is unable to be pivoted
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CA 02410774 2002-12-04
quickly throughout the range of pivotal movement independently of the other
scrapers so as to prevent damage.
The restrictive aspect being the dynamic inadequacy of the geometrical
configuration relative to the responsiveness of the pivoting scrapers.
Limiting
aspects of the pivoting scrapers responsiveness, due to the fact that the
scrapers do
not contact a log in a trailing manner relative to the log feed direction,
resulting in
damage to the rotary debarker ring components of the rotary debarker ring and
to
the log in the form of damaged fiber, reducing the quality of the product thus
potential profits are lost in a wastefully manner. Typically a rotary debarker
ring
as is known in the art is unable to provide an adequate response time with
respect
to the opening and closing of the pivoting scrapers so as to prevent damage.
The
structural requirements of a pivoting scraper able to endure the forces
produced
when contact is made with the end of the log due to this perpendicular
relationship between the log feed direction and the pivotal paths of the
pivoting
scrapers are significant. During the initial contact between the leading end
of a
log entering a rotary debarker ring, the scrapers are required to pivot
quickly so as
to prevent damaged, enabling the scrapers to be forced opened by the end of a
log
upon contact while the scrapers are pivoted as well as rotated on the in feed
side
of the rotary debarker ring. In order to prevent the scrapers from being
damaged
stronger and more rigid scrapers are produced, resulting in a proportional
increase
in the amount of fiber damage additional the opening as well as the closing of
the
scrapers effects the debarking process in a detrimental manner due to the
detrimental aspects of the inertia being proportionally to the mass of the
pivoting
scrapers which results in the scraping edge of the pivoting scrapers either
abruptly
impacting a log upon contact or the scrapers scraping edge being out of
contact
with the surface of a log in the form of a dwell, resulting in bark remaining
on the
log, thus lowering the quality of product.
The restrictive aspect being the functional application and service
performance of
the rotary debarker ring and specific components, with regards to the wearing
of
the rotary debarker ring as a result of debarking process, additionally the
requirement for the scrapers to be repaired in order to salvage the remaining
substantial investment.
The bark is removed by mean of force which is produced by air pressure and
applied to
the surface of a log by means of pivoting scrapers. A rotary debarker ring
which is
required to be stationary or stopped from rotating, so as to enable the
adjustment of the
air pressure is generally less expensive however specific drawbacks or
detrimental
aspects exist, due to this limited ability to control the air pressure during
operation. 'The
ability to adjust the force applied to the surface of the log during operation
is
accomplished by means of an air seal system. The air pressure being externally
produced, contained, supplied, monitored, analyzed and controlled. The air
seal system
is not only costly to produce but requires frequent maintenance as well as
costly
replacement due to the wearing of the seal which is lubricated with oil which
accumulates
in the air bags limiting the performance and life of components.
CA 02410774 2002-12-04
The air bags which are affixed at both ends, one end of an air bag being
affixed to a
gussets within the rotary debarker ring which is stationary relative to the
pivoting
movement of the pivoting scrapers, the other end of the air bag being affixed
to a lever.
The air bags and the levers are protected from damage to the extent that they
are
positioned on the out feed side of the rotary debarker ring. Shafts are
affixed between the
levers and the scrapers. The pivoting axis of the scrapers, levers and shafts
is parallel to
the axis of the rotary debarker ring. When force is applied to the levers a
torque is
transmitted through the shafts to the scrapers. The position of a scrapers
relative to a
leaver is required to be maintained in order to enable the optimum operational
performance and prevent damage, thus the shafts are required to be affixed to
the scrapers
and leavers utilizing securing means such as keys or splines. During operation
the
limiting aspects of the geometrical configuration of a rotary debarker rings
as is known in
the art, which are detrimental to the performance of a rotary debarker ring as
is known in
the art, are compensated for in order to minimize the detrimental effects of
the negative
aspects of the geometrical relationship between the rotational axis of a
rotary debarker
ring and the pivotal axis of the pivoting scrapers, as is known in the art, a
variety of
solutions are employed and applied to the operational procedures requiring
specific
compensation.
Such as the dumping of the air pressure from within the air bags enabling
centrifugal force to open the pivoting scrapers prior to a log entering the
rotary
debarker ring, accordingly a large volume of air is required to replenish the
air
pressure within the air bags to enable the debarking process to continue.
The sorting and feeding of logs accarding to diametric size and orientating
the
logs direction so that the smaller end of a log is the leading end relative to
the
feed direction of a log. Feeding the logs in such a manner that one end of a
log
being debarked is contacting the end of the next log to be debarked, as in the
feeding of the logs one after another without a space between the logs ends,
in
order to minimize the responsiveness requirements by decreasing the range of
pivotal movement required of the pivoting scrapers so as to aid in the
reducing of
the amount of damage caused by the debarking process.
The in feed end of a rotary debarker ring including the scrapers, hubs and
shafts sustain
damage from logs as a log enters and passes through, as well as from the bark
as it is
removed and expelled outwardly. Operational downtime as a result of damaged
components is unpredictable and inevitable with the rotary debarker ring
designs as is
known in the art causing both an inconvenience and additional expense to the
operators.
SUMMARY OF THE INVENTION
According to one aspect of the invention, there is provided an adjustable self
contained
automatic compensating out feed rotary debarker ring comprising a rotary
debarker ring,
a plurality of pivoting scrapers possessing, a scraping edge and a pivoting
axis, being
other than parallel to the rotational axis of the rotary debarker ring,
furthermore the
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CA 02410774 2002-12-04
pivoting scrapers being positioned so as to contact the log in a trailing
manner relative to
the rotational direction of the rotary debarker ring and the log feed
direction, as the log
exits out of the back of the rotary debarker ring and an air system comprising
an air
compressor which supplies the force applied through the pivoting scrapers to
the surface
of a log so as to cause the bark to be removed from the log in a conical spray
outwardly
and away from the log and the rotary debarker ring as the log exits and
controlling means
which enable the force applied to the surface of a log to be increased or
decreased
automatically while being able to be manually adjusted and programmed to the
desired
automatic compensations of the force, by means of a remote control.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE
DRAWINGS
An embodiment of the invention will now be described, by way of example only,
with
the use of drawings in which:
FIG. 1 is a diagrammatic view of the rotary debarker ring assembly and the
support frame according to the invention, shown from three different
perspectives,
from left to right, an isometric front or in feed end view, a side view, and
an
isometric back or out feed end view, respectively.
FIG. 2 is a diagrammatic isometric sectional back or out feed end view of the
rotary debarker ring assembly and the support frame according to the
invention;
FIG. 3 is a diagrammatic isometric exploded sectional back or out feed end
view
of the rotary debarker ring assembly and the support frame according to the
invention.
FIG. 4 is a diagrammatic isometric view of the "X, Y, Z" coordinate system in
which the geometric relationship between the pivoting scrapers axis and the
rotational axis of ring 10, representational of viewing the rotary debarker
from the
back or out feed end is shown.
FIG. 4 A is a diagrammatic front view of the "X, Y" coordinate as described
within the description of FIG. 4.
FIG. 4 B is a diagrammatic side view of the "Y, Z" coordinate as described
within the description of FIG. 4.
FIG. 4 C is a diagrammatic top view of the "X, Z" coordinate as described
within the description of FIG. 4.
FIG. 5 is a diagrammatic isometric back or out feed end view of the rotary
debarker ring assembly and the support frame according to the invention,
showing
a cylindrical shape representative of a relatively small log exiting the
rotary
debarker ring.
FIG. 5 A is a diagrammatic isometric back or out feed end view of the rotary
debarker ring assembly and the support frame according to the invention,
showing
a cylindrical shape representative of a relatively large log exiting the
rotary
debaxker ring.
CA 02410774 2002-12-04
DESCRIPTION OF SPECIFIC EMBODIMENT
The description of a rotary debarker ring, which is capable of being made so
as to be
operable in ether a clockwise or a counter clockwise direction with respect to
a given
view, however the description of a rotary debarker ring which operates while
being
rotated in a clock wise direction as viewed from the back of the rotary
debarker ring and
thus being operable while being rotated in a counter clockwise direction as
viewed from
the front of the rotary debarker ring, further more the front end being the in
feed end, thus
the back end being the out feed end, is as follows:
Referring to FIG. 1, a rotary debarker ring assembly is generally illustrated
at 10.
Refernng to FIGS. 2 and 3, a rotary debarker ring 10 supported by a support 11
and
enabled to rotate on a ring bearing. 'The ring bearing (not shown) being
fitted centrally
between the rotary debarker ring 10 and the support 11, as is known in the
art. The
support 11 is positioned in front of the rotary debarker ring 10 relative to
the longitudinal
feed direction of the log and is conical in shape, with a short cylindrical
bore 12 in the
center portion of the support 11, sufficient in size to enable a log to pass
through the bore
12 forming a funnel like entrance for the log on the in feed front end while
creating the
required clearance for the ring 10 on the other side, thus providing
protection to ring 10.
The ring 10 is also conical in shape and provides the required space within
the ring 10
enabling the containment of the various components required to produce,
contain,
monitor and automatically or manually control the variable force applied to
the surface of
the log during operation. The force being provided by means of air pressure
which is,
produced, contained, and automatically controlled within the primary air
system and
furthermore being, contained and automatically controlled within the secondary
air
system. The two separate air systems being connected so as to produce a single
air
system, each of which, while being connected, are independently automatically
controlled and furthermore being able to be manually over ridden and
programmed by
means of remote control during operation. The air tank generally illustrated
at 13
comprising two circular bands generally illustrated at 14. The circular bands
14
positioned such that the theoretical centers relative to the circular aspects
of the bands 14
exist on the rotational axis of the ring 10. The circular bands 14 while being
contained
within the outer most diameter of the ring 10 are comprised so as the width of
the bands
and the distance between them adequately provides for an air tank 13 to be
sufficient in
size while providing the required space within the ring 10 enabling the
housing of all the
components contained within ring 10. The two bands 14 form the air tank
utilizing a
portion of the conical ring 10 and a covering end cap ring 15. The air tank 13
comprising
an air port 16 and a drainage port 17. The air port 16 is connected to the
compressor 18
which is equipped with an adjustable air pressure switch 19 being operable to
automatically control the operation of the air compressor while additionally
controlling
the air pressure within the air tank, thus controlling the air pressure within
the primary air
system. The air port 16 furthermore being connected to the adjustable over
pressure
relief valve 20. The pressure setting of the pressure switch 19 being limited
so as not to
exceed the pressure setting of the over pressure relief valve 20. The air port
16
furthermore being connected to the electrically controllable air valve 21,
being connected
6
CA 02410774 2002-12-04
so as to supply the secondary air system by means of the releasing of air
pressure from
the primary air system into the secondary air system. The electrically
controllable air
valve 21 operable to control the containment of the air pressure within the
primary air
system while the electrically controllable valve 21 furthermore being operable
to control
the supply of air pressure to the secondary air system by means of the release
of air
pressure from within the primary air system being in the form of the supply of
air
pressure through the connection between the two systems into the secondary air
system.
Thus completing the description of the primary air system. The ring 10
comprising eight
equidistant supports ZZ radially positioned on the ring 10 near the bore 12.
The support
of each of the pivoting scrapers 24 pivotal axis being provided by the
supports 22 which
are positioned in a compound angle relative to the rotary debarker ring's
rotational axis.
The relationship between the pivoting scrapers pivotal axis and the rotary
debarker ring's
rotational axis is expressed more specifically utilizing the "X, Y, Z"
coordinate system in
which a horizontal plane, is represented by the "X" axis, a vertical plain is
represented by
the "Y" axis, and the depth is represented by the "Z" axis, all three
intersect each other at
a central point positioned at the three o'clock position relative to ring 10
as viewed from
the back, while all references with regards to the rotational axis of ring 10
will be made
with the understanding that the longitudinal feed of the log and the
rotational axis of ring
are both parallel to the "Z" axis while the direction of rotation of ring 10
is clock wise
as viewed from the back, while the ring 10 is positioned so as to alien a
single pivoting
scrapers axis so as to intersect the "X" axis at the "Y" and "Z" axis.
Referring to FIG. 4, which illustrates this geometrical relationship within
the "X, Y, Z"
coordinate system as described, in an isometric manner, while the rotational
plane of the
ring 10 is represented by the "X, Y" plane, the rotational axis of the ring 10
represented
by line 35 being parallel to the "Z" axis, while intersecting the "X" axis.
The vertical
center line of the rotational axis of ring 10 represented by line 35-A, which
intersects the
"X" axis, while being parallel to the "Y" axis. A single pivoting scraper's
pivotal axis
represented by line 36 positioned so as to intersect the "X" axis at the "Y"
and "Z" axis.
The rotational path of a pivoting scraper's pivotal axis within the "X, Y"
plain, being
represented by the circle 36-A, positioned so as to intersect the "X" axis at
the "Y" and
"Z" axis.
Refernng to FIG. 4-A which details the vertical center line 35-A, a pivoting
scraper's
pivotal axis 36 as well as the rotational path of the pivoting scrapers axis
36-A, as
described in FIG, 4.
Referring to FIG. 4-B, illustrates the pivoting scraper's pivotal axis
represented by line
36, being at an angle of 22.5 degrees in the "Y, Z" plane relative to the "Z,
X" plane.
Refernng to FIG, 4-C furthermore illustrates the pivoting scraper's pivotal
axis 36 being
at an angle of 22.5 degrees in the "Z, X" plane relative to the "Y, Z" plane.
This
geometrical relationship between the axis of ring 10 and the axis of the
pivoting scrapers
24 enable the scrapers 24 to move out of the way more readily, preventing
damage to the
scrapers and other components as well as to the wood fiber, while enabling the
requirements of operation to be diminished such as the eliminating of the
requirement to
CA 02410774 2002-12-04
dump the air pressure so as to enable the scrapers to open in such a manner so
as to
preventing damaged, this geometrical relationship enables the ability to
supply the air
volume, and air pressure requirements with an air compressor 18 housed within
the ring
10. This geometrical relationship also provides for a more efficient use of
space by
enabling the components to be positioned in an overlapping manner with in the
ring 10,
enabling the containment of eight scrapers as well as the components contained
with in
the ring 10. The variable force is applied to the surface of the log by means
of the
pivoting scrapers 24 being biased by means of the air pressure within air bags
27. The air
bags 27 are affixed directly to the scrapers 24 at the scrapers air bag
mounting tabs 26 on
one end of the air bag, while the other end of the air bags are affixed to the
gussets 23
which are stationary relative to the pivoting movement of the pivoting
scrapers 24. The
air bags 27 comprising a centrally located air port on the end of the air bags
which are
affixed to the internal gusset 23 so as to enable the supply of air pressure
from the air
manifold 28 being contained within the ring 10. The air manifold 28 comprised
of
appropriately sized, hoses, fittings, and clamps, furthermore being comprised
so as to
enable the adjustment of air pressure contained within the air bags and the
manifold 28
by means of an electrically controllable air pressure regulator 29 which
enables the
adjustment of air pressure ether in the form of an increasing or decreeing of
the air
pressure as supplied by the primary air system, additionally an electrically
controllable
valve 30 enabling the release of excessive air pressure from within the
secondary air
system, thus completing the description of the secondary air system.
The combination of the primary and secondary air systems enables the
production and
control of the internally supplied force applied to the surface of a log so as
to remove the
bark from the log utilizing the out feed debarking method. Furthermore the
control of the
force applied to the surface of a log is enabled so as to automatically
compensate the air
pressure proportionally to the logs diametrical size, additionally the
automatic
compensation being adjustable and programmable so as to adjust the pressure
relative to
the conditions, such as temperature and species of the log being debarked by
means of
censors with which the position of the pivoting scrapers and the amount of
force applied
to the surface of the log through the pivoting scrapers is able to be
determined,
monitored, analyzed and controlled, being automatically compensated as
desired. The
bore 12 is equipped with a bore cleaner 32 affixed to the ring 10 so as to
enable the
clearing of the potential accumulation of bark with each revolution of the
ring 10. The
supply of electrical power with which the components contained within the ring
10 are
enabled to function is provided by means of rechargeable batteries 31
contained within
the ring 10.
DESCRIPTION OF THE OPERATION OF THE SPECIFIC
EMBODIMENT
In operation, it will be assumed that the air tank 13 has first been drained
of any water
which has accumulated, due to condensation within the air tank 13 by means of
utilizing
the drainage port 17 and that the air compressor 18 has filled the air tank 13
with
adequate air pressure and has been turned off automatically by the air
pressure switch 19,
8
CA 02410774 2002-12-04
and that the rotary debarker ring 10 is rotating in a direction and at a speed
sufficiently
proportional to the direction and rate of feed of the log to be debarked. As
the log passes
through the bore of the support 11 and contacts the pivoting scrapers 24 which
are forced
open by the log sufficiently so as to remove the bark from the log with out
damaging the
scrapers or the wood fiber to the extent that is typically expected from the m
feed
debarking process as is known in the art. Due to the smoother operating
condition
produced when the pivoting scrapers 24, each of which posses a pivotal axis
being other
than parallel to axis of the ring 10, the air pressure is not required to be
diminished so as
to allow the opening of the pivoting scrapers in order to reduce the amount of
damage
caused by a log impacting the scrapers in a much more abrupt manner as is
common to
the in feed debarking process of the rotary debarker rings as is known in the
art. The
force applied to the log's surface is adjustable while being automatically
controlled by
means of a programmable automatic compensator enabling the automatic
compensation
of the variable force applied to the surface of a log while being able to be
manually
overridden remotely. If there is a need to adjust the variable force applied
to the surface
of the log, being ether to increase or to decrees the variable force being
applied to the
surface of the log manually, the operator, by means of remote control is able
to increase
the air pressure by adjusting the air pressure regulator 29 and while in the
case of
decreasing the air pressure manually, the operator, by means of remote
control, is able to
decrease the air pressure by adjusting the air pressure regulator 29
appropriately while the
valve 30 is opened enabling the releasing of the excessive air pressure from
within the
secondary air system and then closed in order to maintain the desired air
pressure, thus
manually adjusting the force produced and applied to the surface of the log
during
operation.
IMPROVEMENTS
The invention provides for a more cost effective design relative to the
production,
operation, and maintenance of a rotary debarker ring due to, an increase in
the number of
pivoting scrapers, a reduction in the number of individual parts as well as a
reduction in
the and structural requirements of the a rotary debarker ring, furthermore the
designed
usage of individual parts, for example, the support 11 is conical in shape
resulting in an
increase in the proportional strength while, providing not only the supportive
aspects of
the ring 10, but also the protection aspects of the ring 10 as well. The
support 11 while
being less expensive to produce than a ring 10, is considered to be disposable
and is
sacrificial in that it is eventually worn out and replaced while the ring 10
remains
virtually unchanged as a result of operation. Additionally the disposable
aspect of the
scrapers, other wise unable, due to the required expense of production of
scrapers as
presently used in the state of the art.
The efficiency of a rotary debarker ring as a result of the invention is
increased due to the
additional scrapers providing several beneficial aspects, for example:
~ The potential to increase the quality of product.
~ The potential to produce a higher volume of product.
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CA 02410774 2002-12-04
~ The potential to provide a substantial increase in the effective service
life of the
rotational ring bearing.
~ The option of a variable combination of these benefits.
The maintenance of a rotary debarker ring as a result of the invention is
significantly
reduced due to the fact that there are fewer parts as well as a reduction in
the amount of
damage sustained during operation.
~ No air seal system
~ No levers
~ No shafts
~ The rotary debarker ring is not subject to wear to the extent that is
commonly
associated with rotary debarker rings which utilize the in feed debarking
process.
~ The beneficial wearing aspects of the pivoting scrapers being that the
scrapers are
sharpened by the wearing away of the material over time through the debarking
process ultimately wearing to the point that replacement is required.
~ This wearing sharp aspect is due to the angle of the scraping edge during
normal
operating conditions, being sufficient to provide a substantially more
effective
service life relative to the investment requirements while eliminating the
continual repairing of old worn scrapers as well as the related out of service
time.
The aligning of the forces with respect to the dynamics of the operational
function
significantly reduces the stresses which are produced during the operation of
a rotary
debarker ring and thus diminishing the structural requirements of a rotary
debarker ring
and components of a rotary debarker ring, effecting the materials, the volume
of the
materials used, the mass and the resultant relative inertia.
The scrapers in accordance with the teachings of this invention are
constructed utilizing
much lighter materials resulting in a lower production cost additionally
contributing to
the ability to control the pivoting scrapers in favorable manner due to the
detrimental
aspects of inertia. The scraper for this reason is designed to be disposable
and thus is
designed such that it is continually sharpened through the wearing process of
the pivoting
scraper due to the debarking process, thus used until it becomes worn to the
point that
replacement is required.
The effect of the scrapers pivotal movement relative to the air pressure
within the air bags
and the air manifold is that as the scrapers are forced opened by the log the
air bags are
compressed, resulting in an increase in the air pressure within the air bags
as well as in
the air manifold, thus the force applied to the surface of the log is also
increased
CA 02410774 2002-12-04
proportionally. This results in a variation in the air pressure and thus also
in the related
force applied to the surface of a log proportionally to the size of the
opening produced by
the log. This proportional variation however is detrimental to the debarking
process and
thus is diminished due to the additional volume of compressible and expandable
air
provided within the air manifold. Furthermore an additional diminishing of the
proportional variation by means of an automatic adjustment of the air pressure
within the
air bags as well as within the air manifold enabling the automatic
compensation of the air
pressure proportionally to the size of the opening produced by the log.
In the efforts of obtaining the optimal debarking conditions at all times in
order to
increase the productivity while also increasing the quality of product, the
air pressure is
adjusted automatically in order to maintain a more constant force by
compensating for
the proportional variations in the air pressure within the air bags and the
air manifold
relative to the movement of the scrapers proportionally to the size of a log
being
debarked. The automatic compensator contained within the ring 10 utilizes the
information obtained through censors to determine the most favorable operating
pressure
relative to log size as well as other quality and performance factors such as
the debarking
temperature and log species while also being adjustable and programmable
during
operation by means of remote control.
Fiber damage is reduced as a result of the geometrical relationship between
the rotary
debarker rings, rotational axis and the pivoting scrapers, pivotal axis. The
ability for the
scrapers to be forced to an open position over a longer period of time
relative to the
movement of the log, enabled by positioning the pivotal path of the pivoting
scraper to be
aliened closer to the feed direction of the log.
The ability to use lighter materials as well as the allowance of the scrapers
to flex, all
contribute to the reduction of the amount of damage to the wood fiber as
compared to the
amount of fiber damage produced by a rotary debarker ring which employ
scrapers
having a pivotal plane that is 90 degrees to the log feed direction.
It will be understood that while the term "air pressure" has been used to
determine the
force applied to the scrapers it is clear that any force applied to the
scrapers by means of
compressed gas of any kind or any liquid under pressure or electrical or
electromagnetic
or centrifugal force or any means of force applied to the scrapers could also
be used in
accordance with the teachings of the invention and the term "air pressure" is
intended to
cover all such elements.
It will be understood that the term "electrical power" has been used to
express the means
with which the components are enabled. It is clear that stored electricity,
generated
electricity or induced electricity or any form of energy such as the
centrifugal force
present in an operating rotary debarker ring or any other form of energy
capable of
enabling the various components could also be used in accordance with the
teachings of
the invention, and the term "electrical power" s intended to cover all such
elements.
11
CA 02410774 2002-12-04
It will be understood that the term "self contained" has been used to express
that all the
required components are contained within the rotary debarker ring enabling the
production, containment, monitoring, analyzing and automatic control of the
force
required to enable the removal of bark from the log, however a portion of each
of the
eight scrapers extends outside of the physical boundaries of the rotary
debarker ring. It is
to be understood that all the scrapers are to be considered as being contained
within the
rotary debarker ring.
Many modifications to the invention will readily occur to those skilled in the
art and the
specific embodiment described should be taken as illustrative of the invention
only and
not as limiting its scope as define in accordance with the accompanying
claims.
