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Post on 17-Sep-2018
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Overview
Leister and ist photonic activities
TDLS detection principle
TDLS product plattform
Applications
LEISTER Corporate
Production,Logistics
Corporate HeadquarterMarketing & Sales,Administration,Corporate R&D
Axetris,Production
Sarnen, CHKägiswil, CHKägiswil, CH
Corporate Sites
Photonic Sensor Activities at Axetris
Laser Gas SensorsTunable Diode Laser Gas Sensors
IR SourcesBroad band thermal IR emitters for NDIR gas sensors
Micro-OpticsRefractives and diffractives for opticalsensors
p. 6
Reference
GasVolume
Detector
IR Source
Technology - TDLS Measurement Principle
Laser diode scan acrosssingle gas absorption line.
Laser Scan
Laser line
Gas absorption lines
λ
A
λ
A
GasVolume
Laser
Laser signal information:Laser intensity & wavelengthvary linearly with drive current
Gas absorption signal:The detector sees less intensityas the laser hits the gas line
Optical system & reference information: On modulation frequency f
Gas concentration signal:On modulation frequency 2f
I
I
t
t
No gas
With gas
f
2f
λ
λ
Intrinsic reference channelHigh linearity
Laser signal information
Laser Scan
Gasabsorption information
λ
A
Technology - TDLS Measurement Principle
Technology – 1st or 2nd Order
Optical and optoelectronic components (laser & detector) increase significantly in price with wavelength (if available)=> work at 1st or 2nd overtone
Abs
orpt
ion
Wavelength (µm)
4.262.041.57
FundamentalAbsorption Band Envelope1st
Overtone
2nd
Overtone
CO2
1,57 1,571 1,572 1,573 1,574 1,575
COCO
2
Abs
orpt
ion
(a.U
.)
Wavelength
TDLS - Selectivity
TDLS is a high resolutionmeasurementSuperposed bands can beresolved for each gas: Results in high selectivityExample CO2/CO: Envelopes overlap, single absorption lines do not
TDLS - Good for small molecules
TDLS can measure gases with resolved rotation & vibration bands, i.e. gases with small molecules.E.g. alkanes: Ok for CH4, C2H6, but not for longer chains
Electronics
Laser Diode
Mirror
Photo Diode Gas Volume
Technology - Laser Gas Monitor
Sharp laser linehigh selectivity
Intrinsic reference channelhigh, long term stability, calibration-freecontinuous status monitoring
Optical technologycontactless & hot gas measurement
Business Focus
Laser gas detectionPresent Focus on NH3, CH4, CO2, O2Flow through and diffusive set-upsSelf-contained OEM modules, sub-mounts
Applications inProcess control & environmental monitoringIndustrial safety Climate & air conditioningMedical technology
IR Microsystems provides:Self-contained measurementsystem with integrated optics(probe or flow-cell)Digital or analog data output
Customer provides:Input Power (10-30 V)Conditioned/filtered gasPurge gas (where necessary)
Measurementinterface to customer:
TDLS Gas Monitor Set-up
Diffusive: LGD P50 Single point
Flow: LGD F200 (H) Ambient / heated
System Specifications
below detection limitDriftdepending on gas & applic. ppm- or %-rangesMeasurement rangedepending on gas & applic.modular, different path lengthsMeasurement cell layout
ambient, optional up to 190°CMeas. temp. flow-throughflow-throughLGD F200H layout
800 ppm130 ppmOxygenO2
30 ppm5 ppmCarbon DioxideCO2
3 ppm0.5 ppmMethaneCH4
2 ppm0.3 ppmAmmoniaNH3
Peak-to-peak noiseat T: -40°C to +65°C
Precisionat T constantMain Target Gases
LGD F 200 (H) - Specifications
~Compact multigas
~~Acquisition cost
TDLS
~
E-Chem
Calibration-free~~High Stability~~High Selectivity
~Overload damage or ageing
Fast Recovery time
Rugged~~Low cost-over-time
Non-contact measurementCont. Sensor status monitoring
Paramag.NDIR
Characteristics
Gas Sensing Technologies
Selected ApplicationsNH3
SCR / Emission Control
Safety / Refrigeration
Livestock Climate Control
CH4
Environmental Monitoring / Landfill
SCR system monitoring, combustion processes inpower plants, powerstations, diesel engine development
Need to measure NH3 hot (190°C) to 1ppm(acid dew point, water)
LGD F200 H offers real time emission controlwith non-contact measurement in heated sample cell
0.3 ppm2 ppm
Precision at T = const.:Peak-Peak Noise -40°C – 65°C:
SelectivityNon-contact
Main application specific USP
SCR Process Monitoring
Emission Control
0
1
2
3
4
5
6
7
8
9
10
11
12
500 1000 1500 2000 2500
Time [s]
Set 7 ppm
Set 8 ppm
Set 9ppm
Set 10 ppm
Set 0 ppm
Set 2 ppm
Set 6 ppm
Set 5 ppm
LGD F200 NH3 - measurements
resolution
Workplace and site safety monitoring: 1-100 ppmCurrent sensors:
Life time ~ 12 months, 6-months calibration cycleHigh cost for end-userNo sensor status monitoringCross sensitivities / false alarms
microLGD offers better performance at lowercost-over-time
Plant & personnel safety monitoring
0.3 ppm2 ppm
Precision at T = const.:Peak-to-Peak Noise -40°C – 65°C:
Selectivity ReliabilityCost-over-time
Main application specific USP
Safety / Refrigeration
Monitor NH3 to improve health and growth of livestockScrubb NH3 out of exhaust air for environmental protection
Well-suited sensors are not available today
Current sensors:Life time shortened to days by NH3 backgroundCross sensitivities
microLGD enables livestock applications
Ventilation Control & Ammonia Scrubbing
0.3 ppm2 ppm
Precision at T = const.:Peak-to-Peak Noise -40°C – 65°C:
Life-timeCost-over-time
Main application specific USP
Livestock Climate Control
0.3 ppm3 ppm
Precision at T = const.:Peak-to-Peak Noise -40°C – 65°C:
SelectiveHigh dynam. range
Main application specific USP
Landfill / waste water gas monitoring
Monitoring of waste water for CH4emission; landfill de-gasing (safety)
LGD F200 offers real time,monitoring with high dynamic range
Selective measurement of methane
0
2
4
6
8
10
12
14
0 500 1000 1500C
H4 [p
pm]
Time [s]
5 ppm
6 ppm6.9 ppm
7.9 ppm
10 ppm
3.9 ppm
2 ppm
0 ppm
Environmental Monitoring
Summary
The optical, non-contact measurement principle and the intrinsic reference channel and the high selectivity offer significant benefit in a wide range of applications. TDLS moves from high end to upper medium end applications, component cost hinder further penetration into mainstream applications.Leister offers self-contained laser gas monitoring systems to OEMs to use the benefits of this technology in their field of activity.
Thank you for your attention!
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