EXPANSION OF LIQUID
(a) LIQUID IN GLASS THERMOMETER:
PRINCIPLE: It works on the principle of thermal
Expansion
*USE: mercury in glass thermometer is used in
liquid filled opentank, coocking cattle, specific
moltenmetal bath steam line & pipe lines for
fluid flow & laboratory use.
Glass tube thermometer
Principle: Glass tube
thermometer is works on the
principle of Thermal
Expansion.
Purpose: It is used to measure
temperature
(300F to 1200F)
Parts: Glass Bulb ,Capillary
Tube, Scale,
Liquid in glass tube:
Mercury & colour liquid.
Capillary tube
Glass Bulb
Liquid
EXPANSION OF LIQUID
b) STEEL BULB THERMOMETER
*PRINCIPLE: steel bulb thermometer works on
the principle of “thermal expansion”
*MOC: Stainless steel
* USE: when high temp occurred, the glass bulb of
glass tube is in this case steel bulb thermometer is
very useful.
EXPANSION OF LIQUID
STEEL BULB
THERMOMETER
Principle:
Steel bulb thermometer is
works on the principle of
“Thermal Expansion”.
Pointer
Scale
Capillary tube
Steel bulb
EXPANSION OF LIQUID
STEEL BULB THERMOMETER
Parts Of Steel Bulb Thermometer:
(A) Steel Bulb
(B) Capillary Tube
(C) Bourdon tube
(D) scale.
GAS BULB THERMOMETER
Parts Of Thermometer:
Bulb, Capillary tube,
Pressure Gauge.
Uses:
For measurement of temp.
of 350°F to 1000°F range.
Scale
pointer
Dial
Capillary
tube
Gas
Bulb
EXPANSION OF SOLIDS
BI-METALLIC THERMOMETER
MOC:
Bronze & invar metal
strips.
USES:
It is used to measure
temperature.
Pointer
Guides
Shaft
Bimetallic
element
EXPANSION OF SOLIDS
*BI-METALLIC THERMOMETER:
PRINCIPLE: It works on the principle of
expansion of two different metal strip.
ADVANTAGEOUS:
1)It is easy to store & handle
2)It is not easy to break
ELECTRICAL THERMOMETER
(A) RESISTANCE THERMOMETER
*PRINCIPLE:
when temp increases, the
resistance of metal
increases, the resistance
thermometer is works on
these principle
Porcelain
Insulator
Platinum
wires
Alumina
Allumina
powder
Powder
Resistance Thermometer
ELECTRICAL THERMOMETER
THERMOCOUPLE
THERMOCOUPLE:
PRINCIPLE:
Thermocouple is used
to convert thermal
energy into electrical
energy
Voltmeter
Measuring
junction
(cold)
Reference junction
(cold)
Heat source
Thermocouple
ELECTRICAL THERMOMETER
1)RESISTANCE THERMOMETER:
ADVANTAGEOUS:
1)It temp. range is –200°c to 650°c
2)It’s size is very low.
3)It’s measurement is very accurate.
DISADVANTAGEOUS:
1)It’s cost is high
2)Bridge circuit &power supply is necessary for
thermometer
ELECTRICAL THERMOMETER
*Thermocouple:
MOC:
copper-constantant
Iron- --------cromel-allumat
platinam-rhdium
ADVANTAGEOUS:
1)It’s construction is compact
2)It’s temp. rang is –270` to 2500`c
3)calibration is easily made.
INTRODUCTION
Pyrometry is a method to measure temp.
without physical contact.
When body is heated, it produce thermal
energy which is known as hot radiation.
There are two pyrometer.
(1)Radiation pyrometer
(2)Optical pyrometer
RADIATION PYROMETER
RADIATION PYROMETER
Its works depend on the measurement
of radiant energy create by hot body.
It consists of one lens. the total radiant
energy created by hot body when enter
into pyrometer, then its on the detector
by lens. thermopiles is works as a
detector.
OPTICAL PYROMETER
Use: It measures temp. Between 600 to 3000 °c
It is very useful for checking & calibration of
radiation pyrometer. but it is not useful for
temp. recording and controlling.
OPTICAL PYROMETER
ADVANTAGEOUS:
(a)It is a flexible.
(b)Its weight is less.
(c)It is very useful for measurement
of high temp.