Group 1 Experimental and Measurement

7/29/2019 Group 1 Experimental and Measurement

1/46


2/46

1. Ikele, Onas Ojienakhe @00316519

2. Opoku Prince kwaku @00314554

3. Shahin Abdul Razak Shajahan@00318909

4. Adedokun Oluwasegun Isaac @00315601

5. Anene Uche Quincy Chimezie @00314435

6. Arynov Ilyas @00317240

7. Okpaghoro Anthonette @00302388

8. Eric Dankwa @00279531

9. Fasakin Akinwole @00312389

10. William west Isoibim @00324548

11. Benjamin Muyiwa Adegboyega @00315766

12. Chidimma Chilaka @00325389

13. Abdul Taufeeq @00320283

14. Muftahu Nuhu Yahya @00312832

15. Samuel J. Amakiri @00279520

GROUP ONE


3/46

INTRODUCTION

WHAT IS TEMPERATURE?

Temperature is a physical property of matter thatquantitatively expresses the common notions of hot and cold.

TEMPERATURE MEASUREMENT SCALES

Fahrenheit Scale

Centigrade / Celsius Scale Kelvin/ Absolute Temperature Scale

Comparison of Temperature Scales

Fahrenheit Celsius Kelvin

Water boils 212 100 373

Body

temperature

98.6 37 310

Water freezes 32 0 273

Absolute zero -460 -273 0


4/46

THERMOMETERS COMPARE FAHRENHEIT,

CELSIUS AND KELVIN SCALES


5/46

EXPANSION THERMOMETERS

Expansion of solids Bi-metal stripsExpansion of liquids

Liquid-in-metal thermometersExpansion of Gases Gas thermometerChange-of-state thermometer Vapour pressure thermometer Pyrometer cones, bars and rings


6/46

BIMETALLIC STRIP

Description

A bimetallic strip is made up of 2 dissimilar

metals that are fused together, having

different coefficient of expansion.

Advantages

Less expensive

Easy to operate on site readings

Used in small domestic

appliance

Range

- 30C to 550C

Accuracy

1% Full scaledivision

Disadvantage

-it works in smalltemperature range

-it has low accuracy

-Readings cannot be

gotten remotely

brass

flame

invar


7/46

Applicationsit can be used to operate a thermostat

as temperature control device

it can be used to operate a steam trap

used to drive pointer on an instrument


8/46

LIQUID IN METAL THERMOMETER

Rang

e380C - 6000C.

Accuracy

1% F.S.D .

Description

This type of thermometer consists of a large

bulb containing volume of the specific liquid,

bourdon tube, pointer and capillary tube

joining the bulb and the bourdon tube.

When the temperature of the bulb increases,

the liquid inside expands. The expansioncauses the volume to increase which pushes

the bourdon tube up .

Advantage

Direct reading

No external power required

Easy to handle

Disadvantage

Cannot be read remotely

High cost due to corrosion effect of

liquid metal contact.


9/46

Application

Response of temperature for gases is more rapid

then for liquid.

Higher coefficient of expansion than liquids and solids.

Used in electrical ovens to operate On & Off

switch, boilers and air condition


10/46

Description

Vapour Pressure and melting points

can be used to determinetemperatures of a range of liquids and

minerals. These methods can be

carried out using Vapour pressure

thermometers; Pyrometric cones, bars

and rings.

The Vapour Pressure Thermometeruses the variable saturated vapour

pressure of a volatile liquid as a

measure of the temperature.

Range

185C to 315C

Application

Used in steam

traps

Advantages

Does not need ambient

temperature compensation Inexpensive compared to

liquid-in-metal thermometer.

The liquid bulb is small

compared to other expansion

thermometers

Disadvantages

At higher

temperature thescale must have a

wider range than

at lower

temperature

therefore less

accurate

CHANGE OF STATE THERMOMETERS


11/46

Pyrometric Cones, Bars and Rings:Mixtures of minerals are made up in

the form of bars and cones, and

placed in a Kiln. Those of lower

melting points will melt, one will bendover to indicate the temperature of the

kiln, the next cone of higher melting

point is not affected.

PICTURE OF A VAPOUR PRESSURE

THERMOMETER


12/46

Range

200C to 600C

Accuracy

10C

Application

Used in ceramic

industries to

determine Kiln

temperatures.


13/46

ELECTRICAL METHODS OF TEMPERATURE

MEASUREMENTS

Resistance thermometers Thermistors

Thermoelectric thermometers

Measurement of electrical variable

Total radiation pyrometers Partial radiation pyrometers

Chopped radiation pyrometers

Ratio (two-colour) pyrometers

Reflecting hemisphere pyrometers

Optical pyrometers


14/46

RESISTANCE THERMOMETERS

DESCRIPTION

Consist of a length of fine

coiled wire (e.g.. Platinum,nickel, copper)wrapped around

a ceramic core.

Temperature is sensed in the

spiral wire and transmitted to a

meter connected to the leads.

RANGEUp to 600C

ACCURACY Lab

Instrument:

0.01C at 500C

Better than0.5% for

ADVANTAGES

Linear over wide

operating range Wide

temperature

operating range

Good stability athigh temperature

DISADVANTAGES Affected by shock and

vibration.

They need a bridge

circuit, power supply.

Platinum contamination at

temperature over 660C


15/46

Industrial Uses

Air conditioning and refrigeration

servicing.

Food Processing.

Stoves and grills.

Textile production.

Plastics processing.

Petrochemical processing.

Micro electronics.

APPLICATIONS

Laboratory Uses

Air, gas and liquid

temperature measurement

Exhaust gas temperaturemeasurement


16/46

THERMISTORSDESCRIPTION

Thermistors consist of an

element made from

semiconductor material

like metal oxides or oxidemixtures such as cobalt,

copper, iron, magnesium,

manganese, nickel, tin,

titanium, uranium, zinc

RANGE

-100C to 30

C

ACCURACY

0.001C

ADVANTAGES

Rapid response

Higher sensitivity.

Wider application.

DISADVANTAGES

Not suitable for vibrating

mediums

Requires complex

circuitry designs and its

fragile

Thermistors small

thermal mass makes

them vulnerable to self-heating errors


17/46

APPLICATION

Used in digital thermostats

PTC thermistors are used as:

current limiting devices for circuit protection.

NTC thermistors are used as:

resistance thermometer in low temperature measurement of 10k

order.

To monitor the temperature in incubators


18/46

THERMOELECTRIC THERMOMETER

DESCRIPTION

A device consisting of two junctions

of two dissimilar metals, in an electric

circuit; when the two junctions are at

different temperatures, a voltage is

generated by the device; used for

measuring temperature.

There are two types of thermoelectricthermometer and they include the

Base-metal thermocouple (commonly

made of alloys of Nickel-chrome-

aluminium, Iron-constantan and/or

copper-constantan) and the Rare-

metal thermocouple (commonlymade of platinum and platinum-

rhodium)


19/46

RANGE

Up to 800C for Iron

Constantan.

1000 - 2000C for Nickel

Chrome Aluminium.

ACCURACY0.2% -0.75% of full scale

APPLICATION

Used for temperature

measurement for kilns,

gas turbine exhaust,

diesel engines, and otherindustrial processes.

ADVANTAGES

Nickel-Chrome-

Aluminium alloy

eliminates the

problem of rust

Rapidly varyingtemperature can be

measured.

Cheap and easy to

construct.

It can measure

temperature at apoint.

DISADVANTAGES

Inaccurate over a wide

range.

Different thermocouples arerequired for different ranges.

Metals could be affected by

oxidization, and other

degradation.

Cold junction compensations

to be considered. Errors could arise from

prolonged use due to metal

vapours and other furnace

gases thus for each

thermocouple, galvanometer

requires fresh calibration.


20/46

RADIATION PYROMETERS

Radiation is a process in which energetic particles or waves travels through a

medium or space.

Kirchhoff law of thermal radiation states that Radiation emitted by anybody at acertain temperature is equal to the radiation emitted by a blackbody at the same

temperature multiplied by the absorptance.

The black body temperature is described by Plancks law.

C1 = 3.74 * 10-19 KWm2

C2 = 1.439 * 10-2mK

Eb= Amount of energy per unit area of a blackbody.

T= Temperature

= WavelengthRadiation pyrometers are used in places where physical contact temperature

sensors like Thermocouple, RTD, and Thermistors would fail because of the

high temperature of the source.


21/46

TOTAL RADIATION PYROMETER

DESCRIPTION

The total radiation pyrometer

receives all the radiation from aparticular hot body (both the visibleand invisible radiations).

It consists of radiation receivingelement and a measuring device

The heat energy emitted from the hot

body is passed on to the optical lens,which collects it and is focused on tothe detector with the help of themirror and eye piece arrangement.The detector may either be athermistor or photomultiplier tubes

RANGE600- 12000C.

ACCURACY

Non-linear

ADVANTAGES

To measure very

high temperature.High output signal

and moderate cost.

No need to have

contact with

measuring system.

Fast response.

DISADVANTAGENon-linear scale.

Error will occur.

Emissivity of target material affects th

measurements.

APPLICATION


22/46

APPLICATION

Used to measure

temperature of moving

target Used to measure

temperature of a target

where physical contact is

impossible e.g. Moltenmetal.

Used to measure

temperature in corrosiveenvironment.

Used to measure invisible

rays from radiations


23/46

PARTIAL-RADIATION PYROMETER

DESCRIPTION

It is a disappearing filament optical

pyrometer, suitable for measuring hightemperature of incandescent objects, in

annealing and hardening furnaces, in

firing kilns, for measuring the

temperature of molten and flowing

metal or glass as well as incandescent

blocks during forging, pressing orrolling. The temperature measurement

makes use of comparison between the

brightness of an electrically heated and

calibrated incandescent filament

RANGE

800 -20000C.

ACCURACY

1% of measuringrange.

ADVANTAGE

Has light weight, houses all

components of the complete

measuring equipment.

They are easy to operate.

High measuring accuracy.

DISADVANTAGESensitive only to restricted

wavelength.

Reflected radiation can cause

serious errors in radiation

pyrometer at temperature below8000C.


24/46

APPLICATION

For measuring hightemperature of

incandescent objects, inannealing and hardeningfurnaces, in firing kilns e.gCeramics and Cementindustries

For measuring thetemperature of molten andflowing metal e.g. Steelindustries or molten glassas well as incandescent

blocks during forging,pressing or rolling

http://www.processsensorsir.com


25/46

CHOPPED RADIATION PYROMETER

Used to characterize the mechanical or

optical modulation of radiation.

(Primarily, thermal infrared radiation,

intercepted by the infra-red detector).

This is accomplished by an optical

chopper, basically mechanical blades

driven by a suitable electromagnetic

device-which periodically interrupts the

incident radiation from the measured

target to the detector.

During each interruption, the detector is

exposed to a reference radiation,

generally an internal blackbody

reference source having a defined

temperature

APPLICATIONS

To operate pyroelectric detectors.


26/46

ADVANTAGES

Virtually no thermal drift.

Unequalled noise filtering.

High temperature resolution.

Long term stability.

Excellent dynamic compensation

of thermal shock.

To reduce signal noise.

DISADVANTAGES

High construction cost.

Has its weak link in the

optical chopper, as ittends to make

pyrometers unreliable.

ACCURACY

1% F.S.DRANGE

30-550 0C

RATIO (TWO COLOUR) PYROMETER


27/46

DESCRIPTION

A non-contacting device that intercepts and

measures thermal radiation , a process

known as pyrometry.

Ratio pyrometer is a non contact

measurement device which can be used to

determine the temperature of an object's

surface.

Uses two detectors to add up all the

intensity in two wavebands and then relatethe quotient of the two intensities to

temperature

RATIO (TWO- COLOUR) PYROMETER

ADVANTAGES

They can be used to measure moving

targets

They can also be used for measuringtemperatures of objects in vacuum

which are inaccessible due geometry

limitation or safety hazards

Wide useful temperature rangeRatio

pyrometer has fast response.

From subzero temperatures toextreme high (virtually unlimited values)

DISADVANTAGES

The cost is relativelyhigh, especially when

compared to contact

devices.

ACCURACYHighly Accurate


28/46

APPLICATIONS

Moving objects or any surface that

cannot be reached or touched.

Monitoring such operation as glass,

metal, chemical,

cement etc.

Subzero measurements ( in the

foods, electronics, paper,

pharmaceutical, plastics, textile

industries, etc.)

Checking large lines, vessels, steam

traps, and so on, for faulty

operation.


29/46

Description

The temperature is determined

without knowing the emissivity of

the surface, since it is measured

under essentially blackbody

conditions. The radiation detector

is mounted at the top of the gold

plated reflecting cup which is

placed on the hot surface.

Advantages

It is better able to withstand

repeated operation at high

temperature.Disadvantages

less sensitive to emissivity

errors because of the black

body.

REFLECTING HEMISPHERE

PYROMETER


30/46

Application

Used for spot temperature measurement up to

1300 C on all surfaces except unoxidised metals.

It is also used as a laser processing apparatus.


31/46

OPTICAL PYROMETERSDESCRIPTION

Used for temperature

measurement of an object.

The device actually tracks andmeasures the amount of heat

that is radiated from an object.

In an optical pyrometer, a

brightness comparison is

made to measure the

temperature.

As a measure of the

reference temperature, a

colour change with the

growth in temperature is

taken.

The device compares the

brightness produced by the

radiation of the temperature

source with that of a

reference temperature.


32/46

ADVANTAGES

Provides a very high accuracy

with +/-5 degree Celsius

No need for direct body contact

between instrument and object.

Can be used in a wide variety of

applications e.g. moving objects.

Distance is not a problem as

device can be used for remote

sensing.

Ease of use lightweight,

portable, flexible.

DISADVANTAGES

Device can only be used in

applications with a minimum

temperature of 700 degree

Celsius.

Device not useful for obtaining

continuous values oftemperatures at small intervals.

Expensive.

Not useful for measuring

temperature of clear gas.


33/46

Used to measure temperatures of liquid

metals or highly heated materials.

Can be used to measure furnace

temperatures

APPLICATIONS


34/46

Measurement of temperature of

gases

The suction of pyrometer

The venturi-pneumatic pyrometer

The Schmidt radiation method

SUCTION


35/46

DESCRIPTION

The suction pyrometer measures the

true temperature of a gas.

The sensor, more commonly an type

S thermocouple, is shielded by 3

concentric ceramic tubes to minimize

the radiactive exchange with the

surrounding surfaces or flames. The

gas is aspirated through the ceramic

shields at very high velocity

(>100m/s).

Range

S Type (0

1450)C

B- Type (0-1700) C

Accuracy

Pyrometer has an

accuracy of 1.0%

with high response

time of 7-10seconds.

Advantages

Simplicity of

operation.

Easymaintainabilit

y

Durability/

ruggedness

Disadvantage

Overheating can occur

over an extended period

of time.

SUCTION

PYROMETER


36/46

Applications

Metal molten furnace.

It is used in water-tube boilers.

It is used in steel industries.

Hot air balloon.


37/46

VENTURI-PNEUMATIC PYROMETER

DescriptionThis is an instrument which measures gas and

flame temperatures. The gas temperature ismeasured by comparing the gas density at the

unknown temperatures with its density at known

lower temperature. The density measurements

are obtained by venturi restriction using

pressure drops.

Advantages

its rapid rate of

response

its usage in

regenerative furnace

its extensive usage

time of over 15 hours

among others.

Range

0-2500oCAccuracy

30% at

1300oC

Disadvantages

Being expensive,overheating and sensitivity

to variation in surface

temperature.


38/46

Applications

To measure Extreme high temperature

Industrial furnace

Open-hearth furnace


39/46

SCHMIDT RADIATION METHOD

RANGE

Small temperature

gradients.

ACCURACY

The accuracy depends

on the emissivity of the

gas.

ADVANTAGES

They can be used at

unbearable high temperatures

where probes can not beused.

Highly sensitive local

convection.

Not affected by partialtransparent nature of gas.

DISADVANTAGES

They are expensive.

They are cumbersomeand liable to error due to

the emissivity of gas

DESCRIPTION

This method overcomes the

difficulties caused by the partialtransparent nature of gas. A twin-

beam pyrometer is used, one beam

on a hole in the furnace and the

other on a hot region of the lining

which contains a thermocouple.

A mean value of temperature isobtained at optical path


40/46

APPLICATION


41/46

Measurement of heat flux

Plug-type heat-flux meter Radial-disc heat-flux meter

Ellipsoidal radiometer

PLUG TYPE HEAT FLUX METER


42/46

PLUG-TYPE HEAT-FLUX METER.

DESCRIPTION

This instrument measures the

total heat flux incident upon its

plug face conducting the heat

through the plug to the water

cooling at the rear.

DISADVANTAGE

In practice it is usually difficult

to define L and m precisely.

Guard ring systems are notperfect which also affects the

accuracy.

ADVANTAGES

Uses two thermocouples

for measuring heat fluxRANGE

Heat from a solidangle of 2

RADIAL DISC HEAT FLUX METER


43/46

RADIAL DISC HEAT FLUX METER

DESCRIPTION

This instrument measures the total

heat flux by absorbing on the disc

and conducting it away radically to

the instrument

ADVANTAGES

Simple in construction

Can be used in positions

inaccessible to the plug type

DISADVANTAGE

Usually less accurate

and less robust

PRECAUTION

Each instrument requires

individual calibration


44/46

APPLICATION

To measure the direct heat flux upon a furnace


45/46

ELLIPSOIDAL RADIOMETER

DESCRIPTION

Used to measure the total

radioactive flux(radiation)

incoming from the medium

facing the tip of the radiometer

APPLICATION

It is used in the measurement

of temperature of furnaces

MAXIMUM

OPERATING

TEMPERATURE

Furnace 2973K

ADVANTAGE

Traversing measurements

through the flame are also

possible and provide

additional information on

the flame radioactive

properties

DISADVANTAGE

The response time is

of the order of 1min


46/46

THANKS FOR LISTENING

Documents

Group 1 Experimental and Measurement