Note: Descriptions are shown in the official language in which they were submitted.
CA 02423756 2003-03-27
Doc, No, 51-21 CA Patent
Pulp Production Finishing Line Quality Sensor
Field of the Invention
The present invention relates generally to a method and apparatus for
determining a
quality grade of a pulp sample, and more specifically to real time, on-line
determination
of a grade quality of a final pulp product produced by a pulp production
finishing line.
Background of the Invention
In their efforts to meet the demands of today's competitive and worldwide
oriented
market structures, producers of paper pulp are confronted with stringent
requirements for
their supplied pulp product to be of a high, consistent and well-documented
quality.
Market pulp producers use a number of optical and physical properties to
specify the
grade of their product. Tests according to established industry standards are
commonly
used to determine brightness, opacity, bulk, shive content, elasticity,
tensile strength, or
moisture. One of these tests is for example the Canadian Standard Freeness
(CSF) test.
The CSF-test is designed to give a measure of the rate at which a dilute
suspension of
pulp may be dewatered. The drainage rate, or freeness, has been shown to be
related to
the surface conditions and swelling of the fibres, and is a useful index of
the amount of
mechanical treatment given to the pulp.
Currently, pulp producers evaluate pulp quality by manually sampling pulp
bales on a
pulp finishing line, and conducting well-defined quality tests. Drawbacks
inherent to this
approach include obvious sample limitations, as well as time delays, It is
estimated that
the quality of sixty bales of pulp is usually assessed using six grams of a
pulp sample
only. Furthermore, three to four hours are needed to obtain results of the
quality tests.
Also, a variety of diverse tests are usually required to determine the
different physical
and optical properties of a pulp bale.
In view of the shortcoming of the traditional methods of characterizing pulp
samples,
various methods have been proposed to circumvent the intrinsic problems
associated with
standard tests. The prior art teaches different approaches to on-line
monitoring of the
2
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
quality of pulp samples. Trotter et al. (Proceedings of the 47'" Appita Annual
General
Conference; Rotura, New Zealand; 1993, p 651) describe a brightness meter for
measuring the brightness of pulp bales, and a method for on-line measurements
of pulp
brightness. This work focuses on reflectance or brightness only, but does not
address the
issue of obtaining other physical and optical properties of the pulp bale from
the
brightness measurement.
Another real time application for determining pulp characteristics is
presented by Morgan
and Jeune (Proceedings of the Wastepaper VII Conference; Chicago, Illinois,
U.S.A.,
1996). However, this work relates to determination of specks and dirt
particles, rather
than to determination of brightness and elasticity of a pulp sample.
Nilsson et al. as well as Malmstrom report other on-line approaches to pulp
sample
testing. Nilsson et al. (SPIE 3824. 318 (1999)) describe the application of
optical
spectroscopy to paper production. They outline how fluorescence from paper
following
excitation by either ultraviolet or visible light gives information on the
chemical
composition of the paper. 'this information is used for on-line monitoring of
the paper
during production. From these measurements it is for example possible to
determine the
relative shrinkage of paper during drying. Nilsson et al do not describe how
reflectance
measurements are possibly used to determine a pulp quality. Malmstrom (Svensk
Papperstidning 1999, 102(9), 38) reports on a system for measuring the
properties of pulp
in real time. This system combines NIR-spectroscopy with multivariate data
examination,
but does not utilize reflectance measurements.
In WO 01/79816, the applicant being STORA KOPPABERGS BERGSLAGS
AKTIEBOLAG, a method is disclosed for predicting properties of a product that
consists
of cellulose-fibre-based pulp. The method however applies to a sample
quantity, which is
extracted at various points during the production step, and does not apply to
the final
product being pressed into a bale. Other methods disclosed in the prior art,
for example in
U.S. Pat. No. 4040743 to Villaume et al., issued August 7 1977, and U.S. Pat.
No.
5792942 to Hosokawa, issued August 11, 1998, relate to methods and apparatus
for on-
line determination of pulp characteristics, using spectroscopic methods, but
apply to pulp
3
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
slurries only, rather than to a final pulp product produced by a pulp
production finishing
line.
In view of the problems associated with assessing a quality grade of a final
pulp product
produced by a pulp production finishing line, and in view of the restricted
methods and
apparatus known from the prior art, it would be highly advantageous to provide
a method
and apparatus for a real time, on-line assessment of a plurality of physical
properties of a
final pulp product being produced by a pulp production finishing line, the
physical
characteristics relating to a quality grade of the final pulp product.
Object of the Invention
In order to overcome the limitations of the prior art, it is an object of the
instant invention
to provide a finishing line quality sensor for real time, on-line assessment
of a quality of a
pulp sample produced by a pulp production finishing line.
It is another object of the instant invention to provide a method for an on-
line assessment
of a value of a physical property of a pulp sample relating to a quality of a
pulp sample
produced by a pulp production finishing line.
Summary of the Invention
In accordance with an aspect of the instant invention, there is provided a
method for
determining a quality parameter of a pulp sample, the method comprising the
steps of
providing a pulp sample for which a quality parameter is to be determined,
applying a
force to the pulp sample, obtaining at least a value for a spectral response
relating to a
physical property of the pulp sample in dependence of the applied force,
establishing a
relationship between the at least a value for a spectral response of the pulp
sample and a
value for the applied external force, and determining a quality parameter of
the pulp
sample from the relationship between the value for the spectral response
relating to a
physical property of the pulp sample and value for the applied external force.
In accordance with an aspect of the instant invention there is further
provided a method
for determining a value of a physical property of a pulp sample provided by a
pulp
4
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
production finishing line, the method comprising the steps of providing a
plurality of
reference pulp samples with known reference values of the physical property,
determining reference quality parameters for the plurality of reference pulp
samples by
applying an external force to the plurality of pulp samples, and measuring a
spectral
response of the plurality of pulp samples as a function of applied pressure,
establishing a
relationship between the determined reference quality parameters and the known
values
of the physical property for the reference pulp samples, determining a quality
parameter
for the pulp sample by applying an external force to the sample, and measuring
a spectral
response of the pulp samples as a function of applied pressure, and
determining a value of
a physical property of the pulp sample from the determined quality parameter
according
to the established relationship.
In accordance with another aspect of the instant invention, there is provided
a quality
sensor for determining a quality parameter of a pulp sample. The quality
sensor
comprises a tubular shaped pulp sample holder having an open first end and a
closed
second end, the closure of the closed second end comprising a glass window,
the tubular
shaped pulp sample holder for holding the pulp sample, a hydraulic ram
inserted into the
open end of the tubular shaped sample holder and connected to a pump for
applying a
pressure to the pulp sample, a measuring device for measuring at least a value
of a
spectral response property of the pulp sample through the glass window of the;
and a
processor for computing a quality parameter of a pulp sample from a
correlation of the at
least a value of a spectral response property as a function of at least a
value of applied
pressure.
In accordance with yet another aspect of the instant invention there us
provided a bale
press for pressing pulp samples into pulp bales having a pump and a tubular
shaped
quality sensor for determining a quality parameter of a pulp sample being
pressed into a
pulp bale, the tubular shaped quality sensor having a first closed end
attached to a plunger
of the bale press, and having a second closed end, the closure of which
comprises a glass
window, the glass window disposed for facing a pulp sample to be pressed. The
quality
sensor of the bale press comprises an illuminator for sending out light
through the glass
window to the pulp sample, and a light detector for detecting light from the
pulp sample
5
CA 02423756 2003-03-27
Doc. No. 51-2l CA Patent
through the glass window, the light being a spectral response to the light
sent out by the
illuminator.
Brief Description of the Drawings
Figure I displays a schematic block diagram of a prior art pulp production
process;
Figure 2 displays a schematic block diagram of a prior art pulp production
finishing line;
Figure 3 shows a flow chart illustrating a procedure for determining quality
parameters of
a pulp sample according to an embodiment of the instant invention;
Figure 4a displays a BCTMP pulp pressure trajectory for a first pressure
cycle;
Figure 4b displays a BCTMP pulp pressure trajectory for a second pressure
cycle;
Figure 4c displays a BCTMP pulp pressure trajectory for a third pressure
cycle;
Figure Sa displays a polynomial regression curve for assessing a bulk value;
Figure Sb displays a polynomial regression curve for assessing a brightness
value;
Figure Sc displays a polynomial regression curve for assessing a tensile
strength value;
Figure 5d displays a polynomial regression curve for assessing an opacity
value;
Figure 6 shows a flow chart illustrating a procedure for determining physical
properties
of a pulp sample according to an embodiment of the instant invention;
Figure 7 shows a schematic diagram of a quality sensor (QS) according to the
instant
invention; and
Figure 8 displays a schematic diagram of a finishing line quality sensor
(FLIQS)
according to the instant invention.
Detailed Description of the Invention
The instant invention will now be described with reference to a quality sensor
(QS) and a
finishing line quality sensor (FLIQS) in connection with a pulp production
line. used for
assessing a quality grade of a final pulp product produced by said pulp
finishing line. The
6
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
instant invention makes use of a correlation of values for a physical property
of a pulp
sample and quality parameters determined from change in spectral response
properties of
a pulp sample as a function of applied external forces. The values of a
physical property
of a final pulp product relate to a quality of said final pulp product, Of
course, the system
and method according to the instant invention is not restricted to the use
with a pulp
production finishing line, but is generally applicable to situations in which
physical
properties of a pulp sample are to be determined.
A system and method accorditzg the instant invention will be highly
appreciated, when
viewed in the context of pulp production. Referring now to Figure 1, a
schematic block
diagram is presented, illustrating the essential steps of a pulp manufacturing
process. The
process for the manufacture of pulp involves transformation of wood into a
fibrous
material, known as paste, pulp or industrial pulp. At a wood handling station
101, raw
material is received. Logs that are delivered to the wood handling station are
cut and
transferred to a debarking station 102. The debarked logs are then transferred
to a
chipping station 103, where the logs are slashed into wood chips. Next, the
wood chips
are transferred to a pulping station 104.
Different methods of producing pulp have been developed, including chemical
pulping as
well as mechanical pulping. Examples for mechanical pulping methods include
refiner
mechanical pulping (RMP), thermo-mechanical pulping (TMP), thermal refiner
mechanical pulping (TRMP), as well as bleached chemo-thermo-mechanical pulping
(BCTMP). In RMP, pulp is produced by mechanical reduction of wood chips in a
disc
refiner. When wood material is submitted to the action of rotating discs of a
mechanical
refiner, the wood material is progressively broken down into finer particles
and into wood
fibres. A variation of RMP is TMP, in which the raw material is submitted to
hot steam
before and during the refining process, and in which both heating and refining
are
performed under increased pressure. When heating and refining are performed
under
atmospheric pressure, the process is referred to as thermal refiner mechanical
pulping
(TRMP). The steaming applied in the TMP process serves to soften wood the
chips and
results in raw pulp with greater percentage of long fibres and less skives,
when compared
to pulp produced by RMP. Vv.'hen the wood chips are treated with hot steam and
a
bleaching chemical before refinement, the process is then referred to as
bleached chemo-
7
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
thermo-mechanical pulping (BCTMP). The pulp used in connection with the
instant
invention preferably is pulp produced in a pulp station 104 working according
to the
BCTMP process; however, method and apparatus according to the instant
invention
equally apply to pulp produced by other type of mechanical or chemical pulping
processes as well.
The raw pulp stemming form the pulping station 104 is transferred to a
bleaching station
105. Treatment with hydrogen peroxide, chlorine dioxide, oxygen and caustic
soda, or
other bleaching chemicals, is alternated with washing filter cycles. The pulp
now enters a
washing and drying station 106. Possible methods of pulp drying include heat
drying or
pressure drying. Pulp leaving the washing and drying station 106 is referred
to as fluff
pulp. Fluff pulp enters a pulp finishing line 200, where it is pressed and
prepared for
shipping.
Referring now to Figure 2, displayed is a schematic block diagram of a prior
art pulp
production finishing line 200. A first amount of fluff pulp is introduced into
a forming
press 201, and pressed into a first thin layer of a pulp cookie. After this, a
second amount
of fluff pulp is added on top of the first thin layer of the pulp cookie, and
the forming
press 201 presses the second amount of fluff pulp into a second thin layer of
the pulp
cookie. Typically, this process is repeated several times producing a pulp
cookie having
several layers. Depending on physical properties of pulp pressed into layers
of a pulp
cookie, a pulp cookie contains up to four or more layers of pulp. A pulp
cookie is made
as a layered structure, because the volume of an amount of fluff pulp used to
press up to
four or more layers of pulp is typically too large to be introduced into a
pressing chamber
of the forming press 201 at once. After the pulp cookie is formed, it is
transferred to a
transport table 202, from which it is transported to a scale 203. On the scale
203, it is ,
tested whether a pulp cookie fulfills given weight requirements. The pulp
cookie is then
submitted to a bale press 204. The bale press 204 is an integral part of a
pulp production
finishing line. The purpose of the bale press 204 is to mechanically compress
the pulp,
applying pressures reaching and exceeding 5000 PSI, in order to reduce its
volume for
shipping. Therefore, top layer of a final pulp bale leaving the bale press has
been pressed
twice, once in the forming press 201 and once in the bale press 204, and other
layers have
8
CA 02423756 2003-03-27
Doc. No. 51-2l CA Patent
been pressed at least twice, depending on the total number of layers of the
pulp cookie,
which was submitted to the bale press.
A pulp bale leaving the bale press 204 is subsequently submitted to a wrapping
machine
205, tying machines 206, and a marking machine 207. The marking machine 207
usually
labels the pulp bale according to !ot number. Furthermore, the bale label
contains
information regarding quality parameters of the final pulp, such as bulk and
pulp
strength. The final pulp product is then ready for shipment.
According to an embodiment of the instant invention, a method is now
described, which
allows for a real time assessment of quality parameters for the final pulp
product. The
quality parameters are determined by evaluating changes of spectral response
properties
of the final pulp product, or a pulp sample of the final pulp product, as
function of
applied external forces. Values of physical properties are directly related to
quality
parameters of the pulp. Further, values of physical properties relate to a
quality of a pulp
product. Since the bale press is an integral part of a pulp production
finishing line, and
since the bale press produces the final pulp product, it is highly
advantageous to
determine the quality parameters of the final pulp product by evaluating the
spectral
response properties of the final pulp product as a function of pressure
applied to the final
pulp product. by the bale press. Preferably, the spectral response properties
monitored are
optical properties of the pulp, as for example surface reflectance.
Optionally, changes in
other spectral response properties, such as near infrared spectral
fingerprints, due to
changes in applied external forces, are monitored.
The surface reflectance or brightness of a pulp sample depends on the surface
particle
density of individual fiber particles constituting a surface of a pulp sample.
When the
pressure on the pulp sample increases, the particle density increases as well.
At the same
time, surface area coverage of the individual fiber particles decreases. It is
therefore
expected that the brightness of a pulp sample will decrease with increasing
pressure being
exerted on the pulp sample. When the pressure on the pulp sample is released,
the pulp
sample will undergo relaxation, and the surface reflectance is expected to
increase again.
Hom.~ever, a degree of inherent inertness of a pulp sample will counteract the
relaxation
process, so that the changes in surface reflectance due to increasing pressure
are expected
9
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
to be different from the change in surface reflectance due to decreasing
pressure. The
difference in behavior with regard to increasing and decreasing pressure
changes is
possibly used for example to assess elasticity of the pulp sample. Other
factors influenced
by changes in pressure are for example intermolecular interactions between
different
tiber particles involving bonding phenomena such as hydrogen bonding, phase
transitions
of locally crystalline fiber areas, and the like. All these effects influence
the brightness of
a pulp sample to a certain degree, acid it is to be expected that the system
and method
according to an embodiment of the instant invention allow for determination of
a
plurality of parameters from a single measurement.
Referring now to Figure 3, shown is a flow chart illustrating a procedure for
determining
quality parameters of a pulp sample according to an embodiment of the instant
invention.
A pulp sample is provided in step 301. Preferably, the pulp sample is a pulp
sample
produced by a BCTMP pulp production finishing line, and submitted to the
process of
bale pressing. However, the method according to the instant invention is not
limited to
pulp produced in a BCTMP process. Next, in step 302, a force is applied to the
pulp
sample. Preferably, a well-defined external force is applied to the pulp
sample. A well-
defined external force is an external force having a predetermined value
within a
predetermined range of an error margin. According to an embodiment of the
instant
invention, the external force relates to pressure exerted by a pulp bale
press. When a
certain external force is applied, a measurement of spectral response
properties is made at
step 303. For example, when a desired pressure is being applied by the bale
press to the
pulp sample, a surface reflectance of the pulp sample is measured. The
reflectance value
together with the applied pressure constitutes a pressure/reflectance data
point. In
general, the spectral response to a certain external force constitutes a data
point. At
decision step 304, it is determined whether the measurement of another data
point is
desired. If yes, the procedure steps back to step 302 and another external
force is applied
to the pulp sample.
In the example of applying pressure to the pulp sample, another pressure value
is either
higher or lower than a first pressure value, indicating an increase or a
decrease in applied
pressure. Preferably, the loop including steps 302, 303, and 304 is executed
repeatedly,
the external force changing in an approximately continuous fashion. Once a
sufficient
CA 02423756 2003-03-27
L)oc. No. 51-21 CA Patent
number of data points is collected, and the decision step 304 is answered
negatively, the
data points are correlated, and a quality parameter is determined, step 305
The procedure according to Figure 3 is a fast procedure on the timescale of a
pulp
production process. The step 305 of correlating the data points is not the
time limiting
step of the pulp production process, when a pulp sample is compressed to a
pulp bale. In
general, it is possible to assign quality parameters to a pulp bale without
any significant
delay time, a significant delay time being defined as the time required to
complete more
than three bale pressing cycles.
In the following it is described how the method of the instant invention has
been tested
for fifteen pulp samples. Seven of the pulp samples contained 100% aspen BCTMP
pulp
produced by ''Millar Western Meadow Lake" (MWML) of Meadow Lake, Saskatchewan,
five samples contained 100% aspen I3C'fMP pulp produced by "Slave Lake Pulp"
(SLP)
of Slave Lake, Alberta, and three samples contained an aspen-softwood blend
BCTMP
pulp from SLP. The corresponding mills provided values for pulp physical
properties,
which were used in testing the method. The experimental procedure of the test
were as
follows:
i) Condition 2.75g of a pulp sample at "constant temperature and humidity"
room
(CTH room) standard conditions for several hours. CTH room standard conditions
refer
to conditions, in which temperature and humidity are substantially maintained
at 22°C
and 50%, respectively. CTH room conditions are common standard for most of
pulp and
paper tests. According to most standard pulp and paper tests, samples are
conditioned in a
CTH room for at least four hours before testing.
ii) Load the CTH room conditioned sample into a lab press cell having a quartz
glass
window for monitoring spectral properties of the pulp sample while pressing.
2~ iii) Apply increasing pressure ranging ti-om 0 to 5000 PSI to the pulp
sample in
intervals of 50 PSh and at each pressure point, measure brightness of the pulp
sample
was measured through the quartz glass window, using a TechnibriterM standard
laboratory brightness tester.
CA 02423756 2003-03-27
Doc. No. S1-21 CA Patent
iv) Apply decreasing pressure ranging from 5000 to 0 PSI to the pulp sample in
intervals of 50 PSI, and at each pressure point, measure brightness of the
pulp sample
through the quartz glass window, using a Technibrite~~M standard laboratory
brightness
tester.
v) Record a pressure trajectory by recording brightness as function of
increasing and
decreasing pressure.
vi) Repeat steps iii) to v) and record another pressure trajectory for the
same pulp
sample. Steps iii) to v) are referred to as a pressure cycle.
Referring now to Figure 4a-4c, shown are pressure trajectories of a BCTMP pulp
sample
for a first, second, and third pressure cycle, respectively. The data points
display
measured reflectance property R (ordinate, in arbitrary units) as a function
of applied
pressure (abscissa, in PSI). A linear regression fit is applied to the
pressure curves, and
data obtained from the linear regression tit are used for a correlation
analysis. Typically,
a linear regression fit for the second pressure cycle trajectory is used to
obtain data for a
correlation analysis. The second pressure cycle trajectory is preferably
selected, since on
the pulp finishing line 200 all layers of a pulp cookie have been pressed at
least twice,
and the most upper layer of a pulp cookie has not been pressed more than two
times.
However, a correlation analysis is also applicable for data obtained from
other than the
second pressure cycle trajectory. With reference to 1 figures 4a-c, it is
evident that linear
regression curves for pressure cycles result in a similar value for an
ordinate intercept IC.
Preferably, a correlation analysis is performed using a value for ordinate
intercept of the
second pressure cycle trajectory ICS. However, correlation analysis is not
restricted to
ICS. The values for IC or IC2 are quality parameters of a pulp sample. From
the pressure
trajectories, other quality parameters are possibly obtained.
Referring now to Figures 5a-d, displayed are polynomial regression curves for
ICa as a
function of a physical property g, IC", = f~(g) _ ~u" ~ y" In Figure 5a, shown
is a
correlation of brightness b of a pulp sample with ICS. Data for all fifteen
pulp samples are
used, and the goodness of the correlation is reflected in the R'' value of
0.9666. In Figure
5b, shown is a correlation of bulk B of a pulp sample with ICz. Data for the
seven
I2
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
MWML pulp samples are used, and the goodness of the correlation is reflected
in the R2
value of 0.9902. In Figure Sc, shown is a correlation of tensile strength t of
a pulp sample
with IC>. Data for the seven MWML pulp samples are used, and the goodness of
the
correlation is reflected in the Rz value of 0.9406. In Figure Sd, shown is a
correlation of
opacity O of a pulp sample with IC'2. Data for the seven MWML pulp samples are
used,
and the goodness of the correlation is reflected in the R'' value of 0.9819.
The correlation data shown in Figures Sa-d illustrate how a physical property
p of a bulk
sample is determined according to the instant invention. Referring now to
Figure 6,
shown is a flow chart illustrating a method according to the instant invention
for
determining a physical property of a pulp sample. Pressure trajectories for a
plurality of
reference pulp samples with a known reference value for a given physical
property p are
recorded, step 601. Preferably, the pressure trajectories are recorded
according to the
procedure of Figure 3. A value for a reference quality parameter g is
determined for each
of the reference pulp samples, step 602, and a correlation between the
reference quality
parameters g and known values of the physical property p is established, step
603.
Preferably, the correlation is a polynomial correlation p = , f ~(g) _ ~ a" ~
g" . The quality
parameter of choice is IC2. The graphs depicted in Figures Sa-d show that such
a
correlation at least exists for brightness, bulk, tensile strength, and
opacity. Possibly other
physical properties are describable by a polynomial correlation expression as
well. A
pressure trajectory is recorded for a sample with an unknown value for the
physical
property p, step 604. Preferably the pressure trajectory is recorded to the
procedure of
Figure 3. A g value for the sample with the unknown physical property p is
established,
step 605, from which a value for the physical property p is determined
according to the
previously established polynomial correlation expression, step 606.
Referring now to Figure 7, shown is a schematic diagram illustrating a quality
sensor
(QS) according to an embodiment of the instant invention. A pulp sample 710 is
introduced into a sample holder 704. 'the sample holder preferably is of a
tubular shape,
through one end of which is introduced a hydraulic ram 702 for applying a
pressure to the
pulp sample 710. The hydraulic ram is connected to pump, and preferably to a
hydraulic
pump (not shown). The other end of the tubular shaped sample holder is closed
with a
13
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
quartz glass window 706, through which a spectral property of the pulp sample
610 is
measured. The spectral property is measured using a standard measuring device
620, such
as a 1'echnibrite ~~"''. The spectral property data measured by the standard
measuring
device 620, as well as the pressure data applied by the pump are entered into
a computing
device such as a processor (not shown) and a relationship between the spectral
popery
data and the pressure data is analyzed.
Referring now to Figure 8, shown is a schematic diagram of a finishing line
quality
sensor (FLIQS) according to the instant invention. A bale press 802 comprises
a
hydraulic ram 806 connected to a pump 860, the pump preferably being a
hydraulic
pump, for applying a pressure to a pulp sample 810. Connected to the hydraulic
ram 806
is a hollow plunger 812. The hollow plunger 812 is of a tubular shape, having
an open
end facing the pulp sample 810. A glass window 816 closes the open end of the
hollow
plunger 812. Inside the hollow plunger 812, there are disposed an illuminator
816 for
illuminating the pulp sample 810 through the glass window 816, and a light
detector 818
for detecting a spectral response from the illuminated pulp sample 810. The
light detector
is connected to a spectrophotometer 820, and transmits detected light relating
to a
spectral response to the spectrophotometer 820. The spectrophotometer 820
measures a
spectral property of the detected light. Further, the spectrophotometer 820 is
connected to
a processor 840, and transmits data relating to the spectral property of the
reflected light
?0 to the processor 840. The processor 840 is also connected to the pump 860,
and the pump
860 transmits data relating to the pressure applied to the pulp sample 810 to
the processor
840. The computer then correlates the pressure data and the spectral response
data, and
determines a physical property of the pulp sample 810.
In another embodiment of the instant invention, the processor 840 is connected
to a
control unit (not shown), which controls settings for the pulp station 104.
The processor
840 transmits a value for a physical property of a pulp sample 810 to the
control unit. The
control unit compares the transmitted value of the physical property with a
predetermined
value of the physical property, and based on the comparison adjusts settings
of the pulp
station 104.
14
CA 02423756 2003-03-27
Doc. No. 51-21 CA Patent
Readers of the foregoing disclosure will envisage various other embodiments
within the
spirit and scope of the present invention, the breadth of which is of record
in the
appended claims
15
