红外气体传感器原理介绍

June 2010
smartGAS Mikrosensorik GmbH
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InfraInfra-red absorption photometry
The principle is based on the characteristic of molecules to absorb electromagnetical emission (e.g. light) of a specific wave length Because every gas molecule has a different geometric buildup the absorption characteristic is individual. A so called „fingerprint“ The grade of absorption is proportional to the number of molecules. „quantitative analysis“
(Example is for CO2 carbon dioxide)
100 90 80 Transmission in % 70 60 50 40 30 20 10 0 4,1 4,15 4,2 4,25 4,3 4,35 4,4 4,45 4,5 Wave length λ in µ m
June 2010
June 2010
smartGAS Mikrosensorik GmbH
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IRIR-sensor - Measurement principle
(single beam technology)
interference filter IR-radiation
UM
detector
UM
IRIR-radiation source
All combustible gases
Semiconductor
All gases
Chemisorption and heterogeneous catalyst
InfraInfra-red
„fingerprint“
dipole moment 2-atom gases. C-H oscil.
Selectivity
InfraInfra-red absorption photometry
Mostly it is known which gas has to be measured. So the question is not „which gas?“ but rather „how many?“. By knowing the application we can adjust target gas by selecting the best suitable and mechanical adjustments and software.
using
We made it our business to simplify the use of gases by innovative and reliable gas sensor technology.
June 2010
smartGAS Mikrosensorik GmbH
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The history behind smartGAS:
Catalytic combustion (heat of reaction)
Stability / drift
Good in the absence of catalyst poisons
Zero point OK, sensitivity drift
Excellent, due to physical basis, reference signal possible
smartGAS has he knowledge of how to build, programm and calibrate the best sensor solutions for the individual customers application.
June 2010 smartGAS Mikrosensorik GmbH 7
ቤተ መጻሕፍቲ ባይዱJune 2010
smartGAS Mikrosensorik GmbH
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The growth rate 2008 to 2010:
June 2010
smartGAS Mikrosensorik GmbH
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Measure gases – but how?
The technology of smartGAS Mikrosensorik GmbH
smartGAS Mikrosensorik GmbH
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Second step:
Selection of the interference filter in regards to the needed performance of the system
Absorptionsspektrum CO2 Absorption spectrum IR-Filter Transmission Transmissionsspektrum Filter 100 90 80 Transmission in % 70 60 50 40 30 20 10 0 4,1 4,15 4,2 4,25 4,3 4,35 4,4 4,45 4,5 Wave length λ in µm
IR-radiation source IRReference Channel
Dual-detector DualRef. Measurement Channel Meas. Interference filters
Amplifier
UM
The „Dual-Beam Technology“ is used to avoid drift effects which are caused for example by aging of the IR source, soiling of the sample cell or desposits on the detector surface. The reference channel is tuned to a wavelenght where no gas absorbs IR-radiation. It generates a stabel signal which is only changed by external effects which do not result in the measured gas.
Measurement signal M
Modulation =
R – M(0)∤e-αcL R
Gas concentration
June 2010 smartGAS Mikrosensorik GmbH 14
Comparison of usual measuring principles
Pellistor
04/2005 05/2007 07/2007 09/2007 07 /2009 devices,…) Today 12 Employees, market leader in IR dual beam sensors for SF6 and refrigerants, worldwide partner network (Asia, Europe, North America) Foundation of smartGAS as Spin-Off at the University of Applied Sciences in Dortmund Assessement of the smartALERT and certification of the EN-conformance. Involvement of the Zukunftsfonds Heilbronn and enlargement of the authorized capital to 135.000 €. Transfer of the company headquarters to Heilbronn. Constant grow up phase. Several development projects with different customers (deep sea applications, medical
Company presentation
smartGAS Mikrosensorik GmbH Kreuzenstr. 98 D-74076 Heilbronn www.smartgas.eu
The motivation behind the company:
Every day we get in contact with gases, directly or indirectly. Gases are essential but they can be dangerous, too. Gases affect the climate and appeal to our well-being. In engineering, gases are an indispensable energy and instrument in one.
June 2010
smartGAS Mikrosensorik GmbH
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Signal evaluation of a dual beam gas sensor
Stable reference signal R
Intensity signal
I(c)= I(0)∤e-αcL
I(0) = Emission intensity without gas α = Absorption coefficient (specific for the actual gas) L = Length of the absorption route
our system on the IR filters, IR sources
Using the „Lambert-Beer-absorption principle“ the change of LambertLambert Beerintensity is an indicator for the concentration.
amplifier
gas concentration
no gas
alarmthreshold ALARM
signalsignalalteration
time
June 2010
smartGAS Mikrosensorik GmbH
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IRIR-sensor - Measurement principle (dual beam technology)
Operating temperature
500°C– 700°C surface temperature
300°C- 500°C surface temperature
Room temperature
(radiation source is hermetically released)
Saturation Costs
June 2010
smartGAS Mikrosensorik GmbH
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The persons behind smartGAS:
Prof. Dr. Gerhard Wiegleb
Dipl.Dipl.-Ing. (FH) Volker Huelsekopf
Dipl.Dipl.-Ing. (FH) Christian Stein
June 2010
2-defined base line at higher concentrations
I(c)= I(0)∤e-αcL
June 2010
smartGAS Mikrosensorik GmbH
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Sounds simple, but - how does it work?
June 2010
smartGAS Mikrosensorik GmbH
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First step:
Defining the gas depending individual absorption spectrum.