1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2...
-
Upload
nathaniel-dean -
Category
Documents
-
view
219 -
download
2
Transcript of 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2...
![Page 1: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/1.jpg)
1
Gas sensors, cont.
![Page 2: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/2.jpg)
2
Modulation of sensors working temperature
400 ppm NO2
1000 CO + 400 NO2
air
1000 ppm CO
Pulse power supply of the sensors heater
![Page 3: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/3.jpg)
3
Pellistor – type sensors
Pellistor wit a surface catalyst(diam. ca.1 mm)
Pellistor fixed in an encapsulation
![Page 4: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/4.jpg)
4
Thermoconductometric sensors(catharometers)
λG - heat conductivity of a gas
M0 – molecular weight
d0 - molecule diameter
μTAS with separation column and TCD detector for the analysis of chemical composition of a gas mixture
SEM picture of the flow channel with suspended Pt thermoresistor
(magnification 212 x)
020 Md
TG
![Page 5: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/5.jpg)
5
Electrochemical sensors
Lambda sensor characteristics at a working temp. ca. 600oC. Oxygen Lambda sensor of
the finger type installed in an exhaust pipe.
/
15
A F λ – air excess coefficient A – quantity of air F – quantity of a fuel
lnR
RT pE
n F p
![Page 6: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/6.jpg)
6
Oxygen sensor with a current limit causedby a slit.
Thin film amperometric sensor with a current limit due to chemical reactions.
Electrochemical amperometric sensors
![Page 7: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/7.jpg)
7
Optical sensors
Two-diode system for absorptionmeasurement in the NIR region
Methane absorption in a main abs. band 3200 – 3400 nm;1 – diode LED1, 2 - diode LED2,3 - detector
![Page 8: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/8.jpg)
8
Absorption spectrum A and fluorescence emission of DPB compound in nitrogen atmosphere B and oxygen atmosphere C .
Integrated fluorescence sensor coupled with a μTAS microchannel structure.
Optical sensors
![Page 9: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/9.jpg)
9
Structues basd on the field effect
Change of the threshold voltage of a FET transistor as a consequence of interaction with a gas atmosphere.
MISFET type transistor as gas sensor.Gate metal – mostly Pd
![Page 10: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/10.jpg)
10
Mechanism of detection of hydrogen molecules and other hydrocarbons by a thick palladium gate.
Structues basd on the field effect
![Page 11: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/11.jpg)
11
MOSFET arrays
4 MOSFET-s with cathalytic gate in a micromachined structure:1 – MOSFET2 – Al3 – PECVD nitride4 – LPCVD nitride
Power consumption ca. 100 mW at 200oC.
Nordic Sensor
![Page 12: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/12.jpg)
12
Organic composites
Cyrano Sciences Sensor Technology
Thin layer of a composite : conducting carbon in a polimer matrix
![Page 13: 1 Gas sensors, cont.. 2 Modulation of sensors working temperature 400 ppm NO 2 1000 CO + 400 NO 2 air 1000 ppm CO Pulse power supply of the sensors heater.](https://reader036.fdocument.org/reader036/viewer/2022062421/56649e435503460f94b363dc/html5/thumbnails/13.jpg)
13
Measurement with the help of sensor array
Calculation block (microprocessor with software)
Sensor 1
Sensor 2
Meter for measurements of CO and C3H8
concentrations in a mixture.
Gasmixture
Calculatedconcentrations