teco hk series microwave consistency transmitter technical review
TRANSCRIPT
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
HK Microwave Consistency Transmitter
Technical Review 2.0
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
TECO Products & Services
• Stockrite™ consistency transmitters• Drainac™ freeness transmitter• Brainac™ refiner control systems• BrainDrain™ refiner/freeness control• Silica free heatless air dryers• Instrument and valve repair, remanufacture & calibration
• Flow meter expertise and sales
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Today’s Presentation
• How Microwave Measurement Works• The HK Series Microwave• Points on Installation• Calibrating the HK• Things to think about
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Consistency Measurement
• No direct measurement of consistency–Must measure something else which has a relationship to consistency
• Mechanical Transmitters–Respond to apparent viscosity or network strength
• Optical Transmitters–Respond to absorption, reflection or transmission of light
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
How does Microwave work?
• Measures the bulk dielectric constant “ε” of your process
• This is a measure of how fast EM energy can travel through a material
• Usually expressed as a ratio relative to speed of light in a vacuum
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
How does Microwave work?
• Water has a high dielectric constant –About 80
• Cellulose Fiber (and most mineral fillers) have a low dielectric constant–About 4
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
How does Microwave work?
• The bulk dielectric constant of your process is a function of how much water and not-water is in the process
• A higher dielectric means there’s more water and a lower dielectric means less water
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
0 20 40 60 800
20
40
60
80
100
Dielectric
%C
sDielectric vs Consistency
Pure Water
Pure Fiber
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
How does Microwave work?
• You measure the dielectric constant by measuring the phase shift of a signal transmitted through the process
• As the dielectric changes, the phase shift of the signal will also change
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Dielectric vs Phase Shift
100 150 200 250 300 350 4005
10
15
20
25
30
Phase Shift
Die
lect
ricMore Water
More Water
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
How does Microwave work?
• To get consistency, you build a calibration between the measured phase shift, Φ, and your lab’s consistency evaluations
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
• The Compact System• Single piece construction with flange-mounted insertion-pin sensors
The HK System
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
• Modular System• Remote Electronics • Available in insertion or non-insertion configurations
The HK System
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
The HK System
Insertion PinsAvailable in different lengths
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
The HK System
Non-Insertion PinsNon-Invasive Transmitter Bodies
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Notes on Installation
• Choose a vertical pipe as close to a pump discharge as possible–maximizes turbulent mix in the pipe and avoids laminar flow
–Avoid horizontal runs• Ensure minimum pressure of 15 psi
–Higher line pressures are desirable–Reduces the impact of entrained air
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Notes on Installation
• Choose locations with stable process temperature
• Avoid locations subject to large variations in conductivity/salinity
• Insertion pins should be angled–Promotes shedding of trash and avoids stock buildups
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Notes on Installation
• Minimize distance from the transmitter to the sensors
• Protect Cables and Connectors–Don’t over tighten connectors–Avoid water or dirt contamination of coax connectors
–Don’t bend cables
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Intro to Calibration
The Basic Calibration Equation is
Cs = A1*Φc + A0
Cs = calculated consistency valueA1 and A0 are linear coefficientsΦc = temperature-corrected phase shift
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Intro to Calibration
Temperature corrected phase shift Φc is calculated:
Φc = + Φraw + Tk1*(T-Tref)
Tk1 = linear temperature coefficientT = measured process temperatureTref = reference process temperatureΦraw = measured uncorrected phase shift
Note that this is a delta or deviation calculation
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Intro to Calibration
Finally, Φraw is itself a delta:
Φraw = Φm - Φref
Φm = measured phase shift
Φref = reference phase shift
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Intro to Calibration
• Put it all together and the whole thing looks like:
Cs = A1* {Tk1*(T-Tref)+(Φm–Φref)} + A0
• The meter measures red parameters• We define green parameters during setup and calibration
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Intro to Calibration
A1 is the slope of the line
A0 is the y-intercept of the line
%Cs
Φ Phase Shift
Temperature correctionadjusts Φ
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Performing a Calibration
• Successful calibrations consist of several steps–Setup Operating Parameters–Perform the Reference Measurement–Refine Calibration Offset
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Set Initial Operating Parameters
1) Define the linear coefficients A1 and A0
–The initial value of A1 depends on sensor configuration, e.g. -0.235
–The initial value of A0 is 0.0–There is a table in the manual that defines the coefficients for various sensor configurations
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Set Initial Operating Parameters
2) Define the linear temperature correction coefficient
Tk1
–Again, the initial value of Tk1 depends on the sensor configuration. e.g. 1.0
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Set Initial Operating Parameters
3) Define the output 4-20 mA range–i.e., what %Cs produces 4mA and 20mA
4) Optional–Some exteriorly-mounted meters may require that you define ambient temperature correction coefficients because of temperature-induced cable effects from seasonal temperature shifts. This procedure is rare.
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Reference Measurement
• Establishes normal operating regime (Tref & Φref) for the meter– All subsequent measurements are based on deviations away from the normal regime
• Must be completed properly for a successful application– Ensure that total system attenuation falls within the acceptable limits of 5 – 55dB
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Reference Measurement• Process must be stable
– Signal attenuation variance less than 0.5dB– Phase Shift variance less than 20 degrees Phi
• Process sample must be collected and analyzed during performance– Use proper collection procedures & analysis methodology for the best results
• Perform the Reference Measurement Procedure twice for best results
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Reference Measurement• Establishes reference parameters Tref and Φref
• Eetermines nominal signal attenuation for the application
• Useful for diagnosing system behavior if the unit develops problems in the future
• Attenuation changes indicate shifts in the process or in instrument function.
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Reference Measurement• Finally, input the Lab Evaluation of the process sample collected earlier.
• This will adjust the value of A0
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Reference Measurement• Complete Reference Measurement by initiating Measurement Range Computation–software procedure that sets the meter’s limits for consistency.
–These limits are not accessible through the operator interface
–can be calculated manually–process consistencies outside limits will not read correctly
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Refine the Calibration Offset
• Collect several process samples• Analyze the samples and determine the average meter deviation from the lab values
• Adjust A0 accordinglyA0 new = A0 old + 1/n Σ (Lab-Meter)
• The Meter is now calibrated and measuring consistency
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Notes on Calibration• This methodology produces a single point calibration
• Occasionally, better performance is possible by tweaking A1 and A0
• Use Excel to regress a number of process sample-meter data pairs– Use the resulting linear coefficients to adjust the meter’s operational parameters using the technique illustrated in the manual
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Notes on Calibration
• The HK meter supports a linear calibration model only
• To implement non-linear models, you will need to use your DCS– Set to output uncorrected phase shift only– Set A1= 1.0 and both Tk1 & A0= 0.0
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Things to Think About
• Application success requires consideration of these factors:– Temperature– Conductivity– Salt Content – Entrained Air– Fillers and Additives
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Things to Think About
• Temperature– The dielectric constant of water is a function of temperature, which is why we compensate for it
• Conductivity– Changes in conductivity will change the bulk dielectric constant of the process. These shifts will look like changes in consistency, but they’re not. Severe variations may require compensation for best accuracy
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Things to Think About
• Salt Content– Like conductivity, salt content will change the bulk dielectric of the process. Shifts in salt will also look like shifts in consistency
• Entrained Air– Air has a dielectric of about 1.0 and will look like fiber to a microwave signal
– Higher line pressures make big bubbles into little bubbles and minimizes the impact of entrained air
Solution Providers for Process Industries
Thompson Equipment Company, Inc. 125 Industrial Ave., New Orleans, LA 70121
Things to Think About
• Fillers and Additives– Most fillers and additives have high dielectrics and look like water. Some, like TiO2, have low dielectrics and will look like fiber