Multiapplication consistency transmitter

MULTI-APPLICATION CONSISTENCY TRANSMITTER
Dick Lamb and Markku Mustonen
Conmark Systems Inc, Atlanta GA
Define Measure Analyze Improve Control

CONSISTENCY TRANSMITTERS

BLADE CONSISTENCY TRANSMITTERS

ROTARY CONSISTENCY TRANSMITTERS

OPTICAL CONSISTENCY TRANSMITTERS

MICROWAVE CONSISTENCY TRANSMITTERS

ALTERNATIVE OPTION FOR YOUR
CONSISTENCY MEASUREMENT NEEDS
Satron VCT Consistency Transmitter

TECHNOLOGY
• A Total Consistency Measurement
• LED based strobe measurement technique to
measure the consistency
• Built-in signal drift compensation
• High frequency measurement; 10 times a second
• High end electro-optical components up to 140
Celsius
• Sapphire process lens, 7mm
• Location of the optics provides a high signal-to-noise
ratio
• Unique measuring probe design for an easy removal
from process
• Hot tap installation option
• Installation after pump; short lag, and better control
• No regular maintenance is required

ONE TRANSMITTER FOR ALL APPLICATIONS
• Consistency range 0-12%
• Effluent solids less 0.2%
• Tray 0.1-0.4%
• Headbox 0.5-1.5%
• Save-All 0.5-1.5%
• Machine and Blend Chest 2.5-4%
• HW/SW Chests 2.5-4%
• Broke 2.5-4%
• RePulpers 0-5%
• D0 Feed in the Bleach Plant 4-12%
• Washer Feed 1-3%
• Washer outlet 7-12%
• Knotter 3-6%
• Blow Tank outlet 3-6%
• Mechanical Pulping 0-6%
• Recycle Applications 0-5%

INSTALLATION
Short lag, and Better control

EFFLUENT SOLIDS

BLEACH PLANT FINAL CONSISTENCY

EP-PRESS INLET CONSISTENCY

HEADBOX CS% AND ASH%

OFFICE WASTE PULPER CONSISTENCY
0
1
2
3
4
5
6
7
8
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Consistency
LAB VCT^3
Variable amount of ash in the stock

CONSISTENCY CONTROL AND SAMPLING
• The Correct Control and Sampling are just
as important as the Measurement.
• Most of problems with Consistency Control
are not due to the measurement itself.
• Repeatability of the Measurement is a lot
more crucial than the Accuracy.

CONSISTENCY CONTROL
Slow variability cannot be controlled by PID controllers

PRESSURE EFFECT ON CONSISTENCY

FLOW EFFECT ON CONSISTENCY

ONLY WAY TO DO IT RIGHT
SP
Dilution Header
FT
FIC
CT
Pump
I/P
CIC
FT
FRC
Ratio Setpoint
Eliminates the effect of dilution, level and flow
Max Pressure 60 psi
Max Flow Rate 4 ft/s

HD TOWER DILUTION CONTROL

CONSISTENCY CALIBRATION & SAMPLING

23
There is no device that will directly measure pulp consistency
in-line today !
All “Consistency Transmitters” measure some other process
variable.
We must use our process knowledge to understand how to
make a consistency measurement work in each mill
application.

Importance of Sampling and Laboratory Analysis.
Repeatable consistency measurements are very
important to making paper cost effectively. The
Sampling, laboratory equipment and techniques in
use must excellent too so transmitter calibration can
be as accurate as possible.
If the sample evaluation results are inaccurate the calibration
of the consistency transmitter is inaccurate too.

VCT TAPPI 240 SAMPLER
Consistency Measurement Repeatability.
0.01% Cs 10% ??
10% Repeatability of a 4% Consistency Stock
= 4% +/- 0.4% Consistency
Laboratory measures Fiber Only or Total Consistency(Fiber & Ash)
Using Tappi T 240 Test Method
or Tappi T 211 Ash Test Method

How does pulp flow in a pipe ?

A SAMPLE THAT REPRESENTS WHAT THE TRANSMITTER IS READING:
• It must not be taken from a high velocity flow of pulp from the line.
• It must be taken within 2 feet of the consistency transmitter.
• Steps from Sample Extraction to Weighing are the greatest sources of error.
• Sampled stock must be kept in suspension in the sample container and scooped
out of that mixed slurry to make each pad.
• Cover the container so the temperature and moisture content does not change.

29
Where should the consistency sample be taken ?
• Within 2 ft downstream of the transmitter location
• Where the stock is well mixed and distributed evenly across the pipe.
• Choose a location where it is easy to use and access.
• Sampler must be flushed after use so the old fibers don’t become part of a
new sample taken later on. The old fibers can skew the new results.
Who should perform the Sample Extraction and Laboratory Testing
to minimize the variability in the calibration values ?
• It’s best to have 1 Person assigned to do all of the work.
• Enough samples must be evaluated to determine the real consistency
value of the process.

SAMPLING OBSERVATIONS AND SUGGESTIONS:
• Samplers that open quickly to 100% are the easiest to use and provide a
more representative sample for evaluation.
• A large flow rate resulting from high-line pressure allows the sample
extracted to splash everywhere and reduces how well the sample
represents what is flowing in the line.
• The sample must be taken inside the pulp flow and should not include
the “Water Layer”.
• The tester must know how to minimize the effects that make a sample
unusable.

Please remember that understanding how the
process affects the measurements’
techniques, calibrating well, and managing
the measurement technology in use will
create good consistency management results
today !
Thank You !

PLEASE CONTACT US FOR MORE INFORMATION.
INFO@CONMARK.COM

Multiapplication consistency transmitter

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