Temperature measurement By Mitesh Kumar

1. Mitesh kumar
Rall no-10300513026
Applied Electronics & Instrumentation Engg.
Haldia Institute of Technology

2. Bimetallic Strip

3. Bimetallic Dial Thermometer

4. Bimetallic Dial Thermometer working

5. Helical type

6. Video on bimetallic property

7. Filled in system
• Class I – liquid filled
• Class II – vapor filled
• Class III – gas filled
• Class IV/V – mercury filled

8. Class I – liquid filled

9. Class II – vapor filled
II A II B

10. Class II – vapor filled
II C II D

11. Class III – gas filled
Class IV/V – mercury filled
Class V

12. Thermopile

13. Thermocouple Sheath
• Thermocouple junctions are prone to
contamination by gases,liquids,and other
metals.
• The metals contamination alters the
thermoelectric behavior of the device such
that its characteristic varies from that
published in standard table.

14. Table for sheath metals
material Max operating temp(c)
Mild steel 900 ⁰C
Fused silica 1000 ⁰C
Recrystallised alumina 1850 ⁰C
Magnesia 2400 ⁰C
Thoria 2600 ⁰C

15. Ice bath tech

16. Iso-thermal block
• Insert short cu wire b/w both voltmeter terminals and
thermocouple leads and place these new junction on
an iso-thermal block
• This change eliminates the junctions J3 & J4 because cu
is joined to cu at these points
• Place ref. junction not in ice bath but in isothermal
block.
• From the law of intermediate metals we know that
when junctions in series are at same temperature their
makes no change
• Finally J4 and Jref can be replaced by one junction.

17. Iso-thermal block

18. Suction Pyrometers