This document discusses various temperature measurement devices. It defines temperature and explains that it is a measure of how hot or cold a substance is. It then describes several common mechanical temperature sensors including bimetal strip thermometers, gas thermometers, vapor pressure thermometers, and liquid expansion thermometers. The document also discusses pyrometers, thermojunctive devices like thermocouples, thermoresistive devices like thermistors and RTDs, and provides the working principles and typical ranges for each.

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2. GROUP MEMBERS
IHTESHAM UL HAQ
SYED SHEHBAZ AHMAD
FARMAN ULLAH
HAROON KHAN
NAVEED KHAN
AMIR HAMZA
Subject:- IPC
Instructor:- Engr ADNAN SUMROO
BUITEMS

3. Temperature
• Definition:- Temperature is the measure of the hotness or coldness of a
substance is known as temperature
• Coldness is caused because of absence of heat energy.
“motion of molecule due to KE”
• Hotness is caused because of presence of heat energy.
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5. Temperature measuring devices
1. Mechanical thermal sensors.
I. Bimetal strip thermometer.
II. Gas thermometer.
III. Vapour pressure thermometer.
IV. Liquid expansion thermometer.
2. Pyrometers
• Radiation pyrometer
• Infrared pyrometer
• Optical pyrometer etc
3. Thermojunctive.
• Thermocouples (heat energy into electrical energy)
4. Thermoresisitive.
• Thermistors
semiconductor resistance v/s temperature Inverssely proportional
• Resistance temperature detector (RTD)
Metal resistance v/s temperature Directly proportional
(Most commonly for relatively low
temperature)
(used for High temperatures).

6. Thermometer:--
• Definition:-Thermometer is a device that measures temperature or
a temperature gradient.Or
oA thermometer has two important elements:
ophysical change occurs with temperature.
ophysical change into a numerical value.
• Working principle:-The basis of the thermometer’s operation is the
thermal expansion of a working fluid(mercury in this case).
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7. Thermometer
Range :- 0 to 100 °C.
liquid-in-glass thermometers can
achieve a measurement uncertainty
of ±0.01 °C in the range 0 to 100 °C.
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1) Vapor pressure thermometers
• Definition :-
• The saturated vapor pressure of a volatile liquid is used as a
measure of the temperature.
• These thermometers are very sensitive but the scale is not linear.

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Working principle:-
• The liquid is partially stored in a closed vessels or container then the space above
the liquid will consist of evaporated vapors of the liquid at a pressure that depends
on the temperature.
• As the temperature increases the vapor pressure in the liquid increases and the
temperature of the material is measured.
Temperature range is from - 20° C to 280° C depending on the nature of the
gas.

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2) Liquid expansion ( thermometer) OR liquid pressure thermometer:-
• Definition:--
It’s a temperature measuring device whose operation is based on thermal expansion of a liquid.
• Working principle :-
• The insides of the thermo-sensor cylinder, capillary, and Bourdon tube are filled with Volatile liquid which
changes volume with varying temperature.
• The liquid in the thermo-sensor cylinder is expanded and contracted as the temperature changes, and the
pressure change in the Bourdon tube that is transmitted through the capillary is indicated as a temperature.
• Liquid filled thermometers have scales with divisions from 10° to 0.01°C.
• The measurement accuracy depends on the depth of immersion of the thermometer in the medium to be
measured.
• Range:- 80-400 ℃.

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Liquid pressure thermometer
1. A common application of this type of thermometer is measurement of outside temperature from the inside
of a building.

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Gas Thermometer:-
• Definition:- The type of sensors in which the gas is used in the tank which
is increase with the increase in the temperature.
• Working principle:-This sensors is based on basic law of gases, if gas is
kept in a container the pressure and volume is constant and the temperature
is changing. The ratio of gas pressure and temperature is a constant.
OR
• Pressure of a gas at constant volume with increase in temperature.
• The gas thermometer convert temperature information directly into pressure
signals. Useful in pneumatic systems.
• Mostly used inert gases Nitrogen gas is also used.

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Range:- -200 °C to 800 °C.

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4) Bimetallic Thermometer:
Definition:--A bimetallic strip is used to convert a temperature change into mechanical displacement.
The temperature is measured by means of a bimetal system inside the temperature sensor.
Working Principle:-
• The bimetal is made from two metal strips, permanently joined together, each metal
having a different thermal expansion coefficient.
• This causes the strip to deflect in proportion to the temperature variation.
• The actual bimetal system consists of a bimetal strip that is either helically or spirally
wound, depending on the size of the sensor and the temperature range to be measured.
• Any temperature variation causes the bimetal to rotate an attached spindle and it
is indicated by a pointer on a dial.

15. It is used for ON/OFF control in a system.
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• Range:- -70 to 600 °C OR -65 to 430 °C

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Bimetal Helix

17. Radiation Pyrometer:-
• Definition:- its is a type of thermometer which is used for measuring
temperature without any physical contact.
• Working principle:-When body is heated it emit a thermal energy
known as heat radiation. These radiation is passed into a better focus
and passes to a detector then the detector convert these signal into
electric signal and the AD converter convert the signal show measured
value on the display screen.
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18. RANGE:- 103 to 104 °K. For pyrometer -50 to 4000 °C RANGE DEPEND UPON FOR DIFFERENT APPLICATION
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20. Thermistor:-
• Definition:-An electrical resistor whose resistance is greatly reduced
by heating, used for measurement and control of temperature.
• Working principle:-It's resistance is depends upon temperature.
When temperature changes, the resistance of the thermistor changes in
a predictable way. Advantages,The benefits of using a thermistor is
accuracy and stability.
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Range:- −90 °C to 130 °C

22. Resistances temperature detector:-(RTD)
• Definition:- A Resistance Temperature Detector (RTD) is a device with
a significant temperature coefficient (that is, its resistance varies
with temperature)
• Working Principle:-Metal resistance increases with increase in
temperature.
• Valance electron in metal creates the increases in resistance with
temperature.
• Free electron in the valence shell.
• No gap between the valence and conduction band.
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24. Thermocouple:-
• Definition:-A Thermocouple is a sensor used to measure temperature.
• Working principle:-
• Thermocouples consist of two wire legs made from different metals.
• The wires legs are welded together at one end, creating a junction.
• This junction is where the temperature is measured.
• When the junction experiences a change in temperature, a voltage is
created also the change can be measured by an voltmeter.
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Range:-FOR j type= -150 to 745 °C
Range :- For s type= upto 1765 °C (other have above or below)

26. References:-
1. https://www.amazon.com/Process-Control-Instrumentation-Technology-8th/dp/0131194577
(by CURTON D JHONSON)
2.
https://books.google.com.pk/books/about/Principles_and_Methods_of_Temperature_Me.html?id=qfmS7g4JzjwC&redir_esc=y
( by Thomas D. McGee)
3. http://www.hayashidenko.co.jp/en/info04.html
4. http://www.wika.us/upload/BR_RF_Handbook_en_us_18447.pdf
WIKA-Handbook Pressure and Temperature Measurement U.S. Edition
5. https://www.youtube.com/results?search_query=nptel+lec+on+instrumentation+and+process+control
6. https://www.slideshare.net/anandprithviraj/mechanical-temperature-measuring-devices
( by Anand prith viraj)
7. https://www.slideshare.net/mohamedmusmar?utm_campaign=profiletracking&utm_medium=sssite&utm_source=ssslideview
(by Mohamed musmar )
8. https://docs.google.com/file/d/0Bz_j50pBnEarX3JUTDJ6ckFxU2c/view Chemical process controle by George Stephen apolus
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27. Q/A
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Quartz Crystal Thermometer for Measuring
Temperature Deviations in the 10−3 to 10−6 °C Range

28. Thank You
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