Advances in Veneer Dryer Moisture Sensing &...
Transcript of Advances in Veneer Dryer Moisture Sensing &...
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Drying Technology, Inc.
Advances in Veneer Dryer Moisture Sensing & Control
John Robinson & Roger Douglas Drying Technology, Inc.
409-385-6422 www.moisturecontrols.com [email protected]
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Drying Technology, Inc.
Control Veneer Moisture Rather than % Redry
Goals Maximize Veneer Production Rates
Improve Veneer Quality Increase Veneer Recovery
Lower Glue Usage
Since these goals depend on Veneer Moisture Control Veneer Moisture Rather than % Redry
How do we accomplish that?
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Drying Technology, Inc.
Problems with Redry-based Veneer Dryer Control (Long lag time & control of wrong variable)
Feed
6 Min 11 Min
Dead Times
Veneer Dryer
Lag time ∝ Std Dev
Down Stream Moisture Meter
(50 sheet Average)
![Page 4: Advances in Veneer Dryer Moisture Sensing & Controlpelice-expo.com/presentations/Robinson-Veneer-Dryer-Control.pdfProblems with Redry-based Veneer Dryer Control (Long lag time & control](https://reader036.fdocuments.in/reader036/viewer/2022071212/602479263562ca696f3b8bdd/html5/thumbnails/4.jpg)
Drying Technology, Inc.
Exclusive Delta T Model Features That Significantly Improves Veneer Dryer Control
MC = K1(ΔT)p – K2/Sq
An Inside-the-dryer Moisture Sensor
Capability for calculating new setpoint
![Page 5: Advances in Veneer Dryer Moisture Sensing & Controlpelice-expo.com/presentations/Robinson-Veneer-Dryer-Control.pdfProblems with Redry-based Veneer Dryer Control (Long lag time & control](https://reader036.fdocuments.in/reader036/viewer/2022071212/602479263562ca696f3b8bdd/html5/thumbnails/5.jpg)
Drying Technology, Inc.
Feed
Sensor Location
Down Stream Moisture Meter
4.8 Min
6 Min 11 Min
Less Dead Time than Moisture Meter
Dead Times
Dryer
Less Variance than With Moisture Meter Control
Dead time ∝ Std Dev
(50 sheet Average)
Replace % Redry Control with Delta T Inside-the-Dryer MC Sensing & Control
![Page 6: Advances in Veneer Dryer Moisture Sensing & Controlpelice-expo.com/presentations/Robinson-Veneer-Dryer-Control.pdfProblems with Redry-based Veneer Dryer Control (Long lag time & control](https://reader036.fdocuments.in/reader036/viewer/2022071212/602479263562ca696f3b8bdd/html5/thumbnails/6.jpg)
Drying Technology, Inc.
Inside-the-Dryer Moisture Sensor (Solves Lag time Problem)
MC ≈ ΔT
![Page 7: Advances in Veneer Dryer Moisture Sensing & Controlpelice-expo.com/presentations/Robinson-Veneer-Dryer-Control.pdfProblems with Redry-based Veneer Dryer Control (Long lag time & control](https://reader036.fdocuments.in/reader036/viewer/2022071212/602479263562ca696f3b8bdd/html5/thumbnails/7.jpg)
Drying Technology, Inc.
Old ∆T SP
Evaporative Load Increase
New ∆T SP
Actual ∆T Value
Delta T Calculates New Set Point That Maintains Target MC
![Page 8: Advances in Veneer Dryer Moisture Sensing & Controlpelice-expo.com/presentations/Robinson-Veneer-Dryer-Control.pdfProblems with Redry-based Veneer Dryer Control (Long lag time & control](https://reader036.fdocuments.in/reader036/viewer/2022071212/602479263562ca696f3b8bdd/html5/thumbnails/8.jpg)
Drying Technology, Inc.
Improved Veneer Dryer Controls Veneer Moisture not Redry
Delta T Set Point
Delta T Controller Dryer
Delta T Inner (Fast) Loop
Moisture Set Point
Moisture Middle (Slow) Loop
Redry Set Point
Redry Outer (Slower) Loop
![Page 9: Advances in Veneer Dryer Moisture Sensing & Controlpelice-expo.com/presentations/Robinson-Veneer-Dryer-Control.pdfProblems with Redry-based Veneer Dryer Control (Long lag time & control](https://reader036.fdocuments.in/reader036/viewer/2022071212/602479263562ca696f3b8bdd/html5/thumbnails/9.jpg)
Drying Technology, Inc.
Delta T Enables Veneer MC to be Shifted From 10.0% to 10.9%
Delta T Control
Current Control
Same Mean Moisture Production Increase Reduction in Energy
Increase Mean Moisture
M1 M
MC UCL
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Drying Technology, Inc.
Typical Veneer Drying Curve
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Drying Technology, Inc.
Increase Production Rate By Improved Moisture Control
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Drying Technology, Inc.
Synergistic Effect of Air Content on Driving Force for Veneer Drying
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Drying Technology, Inc.
Potential Savings Provided by Delta T
Normal use of Delta T 7.0%
Increase veneer moisture of 0.9% 4.5%
Monitoring & operating at optimum air content 3.6%
Glue Savings from Increase in MC $$
Quality Improvement