Temperature sensor
-
Upload
himani-harbola -
Category
Technology
-
view
1.427 -
download
4
description
Transcript of Temperature sensor
![Page 1: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/1.jpg)
Presented By:HIMANI HARBOLAEIE( 4th year )
TEMPERATURE SENSORS
![Page 2: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/2.jpg)
‡Introduction • Temperature is an important parameter in many control systems.• Temperature is not measured directly like displacement, pressure or flow.
Temperature measuring devices
Electrical instrumen
ts
Non electrical instrumen
ts
![Page 3: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/3.jpg)
‡Sensors covered• Thermocouple.
• RTD.
• Bimetallic thermometer.
![Page 4: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/4.jpg)
†Thermocouple • It is based on the principle of “ seeback effect “.
• Based on generation of thermoelectricity.
•When two dissimilar metals are connected together at two different temperatures, an emf is generated.
• The magnitude of thermal emf depends on the wire material and in temperature difference between the junctions.
• It can be used for both ac and dc applications.
![Page 5: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/5.jpg)
Types of thermocouples• “ J “ type – iron and constantan.• “ K “ type – chromel and alumel.• “E “ type – chromel and constantant.• “ T “ type – copper and constantan.
copper
constantan
Reference junction
Sensing junction
“ T “ Type Thermocouple
![Page 6: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/6.jpg)
Thermopile• Thermocouples may be connected
either in series or in parallel.
• This arrangement is called thermopile.
• In this, all measuring junctions are at same temperature while all reference functions are at another temperature.
• Used to measure temperature of furnance, temperature of moving masses of metal.
A
A
A
B
B
B
B
B are reference junctionsA are heated junctions
![Page 7: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/7.jpg)
• Thermocouples are suitable for wide range of temperature, upto 1800⁰C.
• Widely used in steel industries, heating furnances etc.
• Simple.• Rugged.• No battery required.• Measure wide range of
temperature.• Cheap.
Applications of thermocouple
Advantages
![Page 8: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/8.jpg)
†RTD• Stands for Resistance Temperature
Detector.• It is positive temperature device.• Material used- Pt, Ni, Copper,
Tungesten.• Pt is preferred because it can
withstand high temp., while maintaining excellent stability.• Range: -250 to 1oooC.
![Page 9: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/9.jpg)
• It is used in electrical appliances such as motor, generator etc.
• It is used in engine testing beds.
• Most stable.
• Most accurate.
• More linear than thermocouple.
Applications Advantages
![Page 10: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/10.jpg)
†Bimetallic thermometers• Based on the principle:
i. All metals expand or contract with change in temperature.
ii. The temperature coefficient of expansion is different for all metals.
• It consist 2 strips of different metals welded together.• When welded strip is heated, length of metal changes.• This causes movement of bimetallic strip.• This movement deflects the pointer over calibrated
scale.• Range: -70 to 540C.
![Page 11: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/11.jpg)
![Page 12: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/12.jpg)
• Refineries• Oil burners.• Hot solder tanks.• Hot wire heaters.
• Simple• Robust.• Inexpensive.• Easy to install and maintain.
Application Advantages
![Page 13: Temperature sensor](https://reader035.fdocuments.us/reader035/viewer/2022081413/5477e8eab4af9fcf178b4616/html5/thumbnails/13.jpg)
THANK YOU