Moisture Measurement in Paper Pulp Using Fringing Field Dielectrometry Kishore Sundara-Rajan Xiaobei Li Nick Semenyuk Alexander Mamishev Department of Electrical Engineering, University of Washington, Seattle,USA. S e n s o r s , E n e r g y , a n d A u t o m a t i o n L a b o r a t o r y SEAL M a ver ick T e am
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Moisture Measurement in Paper Pulp Using Fringing Field Dielectrometry Kishore Sundara-Rajan Xiaobei Li Nick Semenyuk Alexander Mamishev Department of.
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Moisture Measurement in Paper
Pulp Using Fringing Field Dielectrometry
Kishore Sundara-RajanXiaobei Li
Nick SemenyukAlexander Mamishev
Department of Electrical Engineering,University of Washington, Seattle,USA.
Sensors
, Ene
rgy,
and Automation Laboratory
SE A L
Maver ickTeam
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 2
Outline
Motivation Introduction to FEF Sensors Experimental Setup Experimental Results Data Analysis Conclusion
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 3
Motivation
Annual worldwide paper production is nearly 312 million tons Huge application market.
Machine controlled using feedback systems Stable, but slow.
10 sec delay on a 2000 m/min machine leads to over 0.2 miles of bad quality paper !!
Solution: Incorporate Feed Forward Control
Wet End Calendaring Dry end
Sensors
FEF Sensors
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 4
Fringing Field Interdigital Sensor
For a semi-infinite homogeneous medium placed on the surface of the sensor, the periodic variation of the electric potential along the X-axis creates an exponentially decaying electric field along the Z-axis, which penetrates the medium.
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 5
Experimental Setup
Pulp is blended using a blender to a consistency of a suspension.
Sensor is attached to the outer side of the base of an acrylic tray.
A guard plane is placed underneath the sensor electrodes to provide shielding from external electric fields.
Drive
Sense Guard
16 cm
4 cm
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 6
Experimental Setup
Sensor Used: Spatial Wavelength : 40 mm Finger Length : 160 mm Penetration Depth : 8 mm
Wall thickness of the tray : 5 mm RCL Meter : (Fluke Manufactured, Model PM6304)
Single Channel Measurements One Volt RMS Sinusoidal AC Voltage 50 Hz to 100 kHz Frequency Range
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 7
Electrical Measurements
All electrical parameters are near-linearly dependent on moisture concentration.
104
9294
96
2468
10
x 106
Frequency (Hz)Moisture (%)
Ad
mit
tan
ce (
S)
104
9294
96-87.6-87.4-87.2
-87-86.8
Frequency (Hz)Moisture (%)
Ph
ase
(deg
)
104
9294
96
18
19
20
Frequency (Hz)Moisture (%)
Cap
acit
ance
(p
F)
104
9294
965
6
7
x 10-12
Frequency (Hz)Moisture (%)
Co
nd
uct
ance
(m
ho
/Hz)
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 8
Cole-Cole Plots
The phase variation is inadequate to obtain a semi-circle Greater frequency range is required.
0 2 4 6
x 10-7
0
2
4
6
8
10
12x 10
6
Re[Y], [ohms]
Im[Y
], [
oh
ms]
91 %92 %93 %94 %95 %96 %
0 2 4 6
x 10-19
0
0.2
0.4
0.6
0.8
1x 10
-5
Re[Z], [ohms]-I
m[Z
], [
oh
ms]
91 %92 %93 %94 %95 %96 %
10/23/2003 SEAL Lab, Dept. of EE, University of Washington. 9