Experimental &

Measurement Methods

Experimental & Measurement

Methods

Temperature and Flux

PressureGas

MeteringGas Quality

MEASUREMENT OF

TEMPERATURE AND HEAT

FLUX

• In terms of kinetic energy, temperature can be defined as

the measurement of the average kinetic energy of the

particles in a sample of matter.

• Heat is defined as the transfer of kinetic energy from one

medium or object to another or from source to medium or

object.

• Hence it can be said that temperature is simply an effect of

heat.

• There are many scales that can be used for temperature

measurement. They include:Centigrade or Celsius Scale

Fahrenheit Scale

Kelvin Scale

INTRODUCTION

A Flowchart Summarizing The Instruments for Temperature

Measurement.

TEMPERATURE MEASUREMENT

EXPANSION THERMOMETERS

BIMETAL STRIP

THERMOMETER

LIQUID IN GLASS THERMOMETER

LIQUID IN METAL THERMOMETER

GAS THERMOMETER

VAPOUR PRESSURE

THERMOMETER

PYROMETRIC CONES, BARS

AND RINGS

ELECTRICAL METHOD OF

TEMPERATURE MEASUREMENT

RESISTANCE THERMOMETERS

THERMISTORS

THERMOELECTRIC THERMOMETERS

(THERMOCOUPLES

RADIATION AND OPTICAL

PYROMETRY

TOTAL RADIATION

PYROMETER

PARTIAL RADIATION

PYROMETER

CHOPPED RADIATION

PYROMETER

RATIO PYROMETER

REFLECTING HEMISHERE PYROMETER

OPTICAL PYROMETER

BULK TEMPERATURE MEASUREMENT

SURFACE TEMPERATURE MEASUREMENT

TEMPERATURE OF GAS

MEASUREMENT

SUCTION PYROMETER

SCHIMDT RADIATION

METHOD

VENTURI PNEUMATIC PYROMETER

HEAT FLUX TEMPERATURE MEASUREMENT

RADIAL-DISC-HEAT FLUX-

METER

ELLIPSODIAL RADIOMETER

PLUG TYPE HEAT FLUX METER

Applications

Advantages

Inexpensive

Provides direct reading

Has a rugged design

Disadvantages

Narrow operating

temperature range

Not very accurate as

compared to RTDs and

Thermocouples

Not suitable for very low

temperatures

EXPANSION THERMOMETERSBI-METAL STRIP

Control thermostats

Drive a pointer on an instrument

Applications

• Boilers

• Heat exchangers

Advantages

• They are not fragile

• Provide accurate readings

Disadvantages

• Liquid in thermometer may need to

be shaken down before usage

EXPANSION THERMOMETERS cont’d

Liquid-in-Metal Thermometer

Advantages

• Rapid response to temperature change

• Wide temperature range

Disadvantages

• Difficult to handle.

Applications

• Installed in most piping and

tanks which provide direct and remote

temperature reading.

EXPANSION THERMOMETERS cont’d

Gas Thermometer

Applications

Used in:

• Pipelines

• Boilers

• Heating systems

Advantages

• Small bulb size

• It is less expensive

Disadvantages

• The scale is not linear

• It has a slow response rate.

EXPANSION THERMOMETERS cont’d

Vapour-Pressure Thermometers

Advantages

• Are useful if clarification is required

that the temperature of a piece of

equipment has not exceeded a certain

level.

Disadvantages

• Accuracy defers based on

interpretation.

Applications

• Used to determine kiln temperature in

the ceramic industry.

EXPANSION THERMOMETERS cont’d

Pyrometric Cones, Bars and Rings

Applications

• In petrochemical processing industries

• To measure the temperature of fluids.

Advantages

• They require no cold junction

measurement.

• Quite stable at high temperatures

• They have a high operating temperature

range

Disadvantages

• Cannot be used to measure rapid

temperature changes

• Slow response speed

ELECTRICAL METHODS OF TEMPERATURE

MEASUREMENT

Resistance Thermometers

Applications

• Automobiles

• Digital thermometers

• Microwave,

• Circuit protector

Advantages

• Selection for a particular application is

simple.

• They are highly sensitive to minute

changes in temperature.

Disadvantages

• Low temperature range

• Fragile

ELECTRICAL METHODS OF TEMPERATURE

MEASUREMENT cont’d

Thermistors

Applications

Used to measure temperature for;

• Diesel engines

• Kilns

• Gas turbine exhaust

Advantages

• It is able to measure a wide range

of temperatures.

• Less expensive as compared to

other temperature measuring

devices.

Disadvantages

• Measurement of two temperatures

are necessary. Need to be

measured.

• Errors could occur due to its

complexity

ELECTRICAL METHODS OF TEMPERATURE

MEASUREMENT cont’d

Thermocouples

ELECTRICAL METHODS OF TEMPERATURE MEASUREMENT cont’d

MEASUREMENT OF THE ELECTRIC AL VARIABLE

Wheatstone Bridge

•The Null Method: Gives the highest

sensitivity and accuracy. Gives spot

reading only.

CRITERIA: Bridge should be balanced

when taking the reading .

•The use of the “out-of-balance

current”. At a specified temperature on the

galvanometer, the resistances are adjusted

to give a zero reading so that any

deviation from this would result in a

deflection. The deflection on the

galvanometer can be calibrated to indicate

temperature directly, by comparing it with

a standard resistance thermometer.

Applications

Can be used for;

• Situations (example; furnace)

involving extreme temperatures.

• Moving object

Advantages

• Direct contact with object of

concern is not necessary.

• Measures temperature of all

wavelengths.

Disadvantages

• Installation cost is high.

• Requires regular maintenance

RADIATION AND OPTICAL PYROMETRYTotal- Radiation Pyrometer

Advantages

• A sensitive waveband can be specified for particular temperature-measuring requirement.

• Can detect fast temperature changes.

• They are highly sensitive at short wavelengths.

Disadvantages

• Installation cost is high

• Maintenance must be done regularly

• Sensitive to only a restricted waveband

RADIATION AND OPTICAL PYROMETRY cont’dPartial-Radiation Pyrometer

Application

• To measure the temperature of aluminium extrusions.

Advantage

• The sensitive waveband can be adjusted depending on the application required.

Disadvantages

• High installation cost

• Requires regular maintenance.

RADIATION AND OPTICAL PYROMETRY cont’dChopped-Radiation Pyrometer

Applications

Used in;

• Cement kilns.

• Measurement of the temperature of liquid metals

Advantages

• Suitable for high temperature levels

Disadvantages

• They are more expensive than the single waveband partial radiation pyrometer.

• They are dependent on detector stability.

RADIATION AND OPTICAL PYROMETRY cont’d

Ratio (Two-Colour) Pyrometer

Applications

• Suitable for spot temperature

measurement on all surfaces, with

unoxidized metals as the only

exception.

Advantages

• The Silicon solar cell has a faster

response time and is able to

withstand repeated operations at

high temperatures.

Disadvantages

• Not so sensitivity to emissivity

errors.

• Expensive

RADIATION AND OPTICAL PYROMETRY cont’d

Reflecting-Hemisphere Pyrometer

Applications

• Used to obtain accurate

measurement of furnaces and

molten metals temperatures.

Advantages

• It is very accurate

• Measurement is independent of

the distance between target and

measuring instrument.

Disadvantages

• Unsuitable for taking continuous

temperature readings

RADIATION AND OPTICAL PYROMETRY cont’dOptical Pyrometer

• As long as the sensor used in measuring the bulk temperature is

completely surrounded by the medium and immersed to an adequate

depth, corrections are not required for transient mass or heat transfer

effects, conduction effects, radiation or velocity effects.

• Resistance thermometers and thermocouples are commonly used to

measure industrial bulk temperatures.

MEASUREMENT OF THE BULK TEMPERATURE OF

SOLIDS AND LIQUIDS

• Surface pyrometers can be used to measure the surface temperature of

solids and liquids when the surface is accessible.

• The temperature detecting elements (thermocouples) needs to be fixed

in place before heating the surface, when the surface is inaccessible or

when continuous measurements are required.

MEASUREMENT OF THE SURFACE TEMPERATURE OF

SOLIDS AND LIQUIDS

The Metal Suction Pyrometer

MEASUREMENT OF THE TEMPERATURE OF

GASESThe Suction Pyrometer

To measuring

instrument To suction pump

Sheathed thermocouple 1.59mm

diameter

Stainless steel hood 6.35mm diameter

Asbestos spring

125mm900mm

Application• It can be used on equipment of all

sizes, because of its relatively

small size and low flow rate.

Advantages•It is portable

•It has high response speed both

under suction or non suction

conditions

Disadvantage•The thermocouple may have a

slow response speed due to the

concentric ceramic shield getting

blocked by dirty gases.

The Water-Cooled Metal Suction Pyrometer

Application

• Several industries

Advantage

• It has a very high temperature

response speed.

Disadvantage

• Insufficient water flow can

cause overheating which

damage the instrument.

MEASUREMENT OF THE TEMPERATURE OF GASES cont’d

The Suction Pyrometer

Tube 305mm long, 14.3mm outside diameter, 0.711mm

thickTube 321mm long, 11.1mm outside diameter, 0.711mm

thick

To

me

asu

ring

instr

um

en

t

To suction pumpWater outlet

PTFE swarf6.35mm spider

O’ rings

6.35mm chock, 2.44mm inside diameterSheathed thermocouple

1.59mm outside

diameterTube 6.35mm outside diameter, 4.5mm inside diameter

Water inlet

•This was developed to be used with the

portable suction pyrometer as a high

temperature accessory.

Applications

• Used in combustion chamber measurement

Accuracy

• Depends on the emissivity of gas

Disadvantages

• The temperature obtained is a mean value along the optical path through

the gas, this is not acceptable for large temperature gradients.

• High Installation cost

MEASUREMENT OF THE TEMPERATURE OF GASES cont’d

Schmidt Radiation Method

Application

• Used in conditions that require rapid temperature measurement

response.

Advantage

• High temperature response rate.

Disadvantages

• They are bulky thus they are not easy to move around.

MEASUREMENT OF THE TEMPERATURE OF GASES

cont’d Venturi-Pneumatic Pyrometer

Advantage

• It is an accurate means of

measuring heat-flux

Disadvantage

• It is difficult to construct

MEASUREMENT OF HEAT FLUXPlug-Type Heat-Flux Meter

Probe cooling

Plug cooling

Plug

Guard ring

Thermocouples

Application

• Used in positions

inaccessible to the plug-

type heat-flux meter

Advantage(s)

• Simple in construction

• Can be used in positions

inaccessible to the plug-

type heat-flux meter.

Disadvantage(s)

• It is less accurate and less

robust as compared to the

plug-type heat-flux meter.

MEASUREMENT OF HEAT FLUX cont’d Radial-Disc Heat-Flux Meter

Foil disc (e.g.

constantan)

Connecting wires (e.g. copper)

Instrument body (e.g. copper)

Water-cooled

probe or

housing

Application(s)

Used in;

• Fire testing

• Furnace

• Flame radiation

measurements

Disadvantage

• Cannot monitor rapid

changes of incident

radiation due to slow

response time

MEASUREMENT OF HEAT FLUX Ellipsoidal Radiometer

Cooling water

Cooling water

F

CopperStainless

steel 20-25

Constantan wires

Thermocouple junctions

Nitrogen

Ellipsoid

e = 0.5

Δv

MEASUREMENT OF

PRESSURE

• Pressure simply put is the measurement of force per unit area

exerted by a fluid or solid on a surface. - Pascal (Nm-2); Bar

(105); Pounds Square inch (psia)

TYPES OF PRESSURE Absolute Pressure: refers to the difference between the fluid pressure and

the pressure in a complete vacuum.

Differential Pressure: this refers to the measurement of the difference

between any two pressures.

Gauge Pressure: this is a differential pressure measurement where one

pressure is the pressure of the atmosphere.

DEFINITION OF TERMS

MEASUREMENT INSTRUMENTS

LIQUID-COLUMN

MANOMETERS

FORCE-BALANCE PRESSURE

GAUGES

• U-TUBE

• WELL-TYPE

• INCLINED-TUBE

• DIFFERENTIAL-LIQUID

• MICROMANOMETER

GAUGES WITH

MECHANICAL

TRANSDUCERS

GAUGES WITH

ELECTRICAL

TRANSDUCERS

• PISTON TYPE

• RING-BALANCE TYPE

• BELL-TYPE

• THE BOURDON-TUBE

• DIAPHRAGM TYPE

•BELLOW TYPE

• STRAIN GAUGE

• LOAD CELL

•CAPACITOR

MICROPHONE

LIQUID-COLUMN MANOMETER

Principle: This involves balancing

pressure due to a fluid by the

pressure produced in a column of

liquid (usually mercury because

of its high density and low vapour

pressure) of known density.

PB - PA = gph

Applications: Used for measuring

differential pressure

Advantages: It is relatively cheap to

acquire, very accurate and

sensitive

Disadvantages: It is fragile, very

sensitive to temperature changes

LIQUID-COLUMN MANOMETER CONTD

Range of up to 800 mmHg

and Accuracy of +0.5%

Range of up to 400mm of

Water and Accuracy of +3%

• Principle: Guages here measure the pressure due to a liquid

by “balancing it against a known weight” or “by measuring the

deformation or strain it produces over a known area”

• Transducers: are devices that are capable of translating

applied pressure into mechanical displacement or electrical

output on gauges that can then be read off or recorded. There

are two types of transducers; electrical and mechanical.

FORCE-BALANCE PRESSURE GAUGES

FORCE-BALANCE PRESSURE GAUGES

Advantages: The hydraulic

type takes high impacts,

insensitive to temperature.

Pneumatic load cells

intrinsically safe. They

contain no fluids

Disadvantages: The hydraulic

type is expensive and

complex. The pneumatic type

has slow response and

requires clean, dry air

LOAD CELLAccuracy: 0.03–0.25 % full scale

• REPEATABILITY

• ACCURACY

• LONG TERM STABILITY

• HYSTERESIS

• NON-LINEARITY

• BEST STRAIGHT LINE

PERFORMANCE CHARACTERISTICS OF PRESSURE

TRANSDUCERS

FORCE BALANCED Pressure gauges

The definition of force balance pressure is balancing the known weight against to

unknown weight by applying known weight mass or by the strain or deformation.

Deformation - characterizes as transition of a body from initial form to present

form.

Strain - is characterized by force created by the elasticity of an object.

The pressure gauges applying strain or deformation principles are following:

The Bourdon-tube Type

The Diaphragm Type

The Bellows Type

1. PISTON TYPE (550 Bar) 2. RING BALANCE (100 Pa) 3. BELL TYPE (300 Bar)

Gauges: piston type, ring balance & bell type

1.BOURDON-TUBE 2. DIAPHGRAM TYPE 3. BELLOW TYPE

Measurement of Strain or Deformation

Calibration is a comparison between measuring instruments. which

is one device is already known of correctness and another

calibrating device is adjusting with known device. The

calibration is carrying process of adjusting the indication on a

measurement instrument to agree value of the applied standard,

with a specified accuracy.

The known of correctness device is named as standard. And

another calibrating device is called test instrument or unit under

test.

The Primary Standard Calibration can be performed only in lab

condition by using dead weight testers to new devices to agree

of manufactures specifications.

Primary & secondary standard calibration

Dead weight tester (DWT)

Dead Weight Testers (DWT)

are called so in reason of

utilization of dead weights in

determination of working

pressures in sealed and

compressed fluid system.

Gas Quality

INTRODUCTION

• The aim of any engineering project is to maintain an itch free

process that is both safe and economical, this sums up the reason

why the quality of gas is measured.

• Gas quality measurements are based on rigid specification and

regulations of controlling legislation.

CRITERIA FOR GAS QUALITY

MEASURMENTS

•Determination of methanol in gas

•Measurement of water and hydrocarbon dew points

•Measurement of oil fog concentration in gas

•Odorimetry and leak detection

•Measurement of total sulphur and hydrogen sulphide concentration in gas

•Measurement of calorific values, relative density, wobbe number and aeration

number of gas

Procedure/Methodology

APPLICATION : Used in pigging procedure for removal of residual

water in new and existing lines; as this helps to prevent gas hydrate in

transmission lines.

• By lowering the hydrate formation temperature below ambient

temperatures using a hydrate inhibitor.

• Either methanol or glycol can be used (or both), which will lower the

formation temperature significantly. To get the methanol (or glycol) into

the pipeline, the

• Hence, the pigging procedure is repeated with a large slug of methanol.

MEASUREMENT OF WATER AND HYDROCARBON

DEWPOINTS

(U.G.C. DEWSCOPE)

The purpose of this measurement is to prevent the formation of retrograde

condensate when the pressure reduced hence measurement are made to

determine how much the dewpoint of hydrocarbon and water has to be

depressed to prevent the phenomena called RETROGRADE

CONDENSATION.

MEASUREMENT OF OIL FOG

CONCENTRATION IN GAS

• long with the use of dry natural gas in distribution systems comes the

problem shrinkage of rubber sealed rings in jointed mains.

Fig.: Rubber sealing ring

• The apparatus used for measurement of oil in gas is OIL

IMPINGEMENT APPARATUS

• APPLICATION: It helps to prevent leakages as oil vapour is

absorbed by the sealing rings and causes them to swell

• TYPICAL LIMITS : As low as 5 – 10mg

Natural gas

Odourless

Colourless

Natural Gas

• A major spur to the development of gas odorants and odorizers

was the March 18, 1937 natural gas leak that blew up a school in

New London, Texas, killing 294 children and teachers.

The odour is added to the gas.

Odour Gas

Mercaptant

Measurement of odour

Measurement of odour

Subjective methodTrained personnel known as rhino-

analysts

Analytical methodsTracing the sulphur

compounds contained in odorants

Subjective Method

The Watson House

Odorimeter

Rhino-analyst

s

Analytical Method

British Gas Odorant

Separating and

burning the Sulphur

Lea

k D

etec

tion

Gasco Seeker

Flame ionisation

Gasco Seeker Flame Ionisation

Natural gas from some wells throughout the world contains hydrogen

sulfide and other sulfur bearing compound. Natural gas with high

concentration of sulphur is called sour gas. It is necessary to remove

these sulfur bearing compounds form the gas, this process is called

‘sweetening; the gas. The purpose of this process is to preserve human

safety, decrease the corrosion in pipelines and to control odor in the gas.

Sulphur and hydrogen sulphide concentration

measurement devices

Mea

sure

men

t D

evic

esThe Barton

sulphur titrator

The British Gas SulphurSelectiveDetector

Component Analysis

(Chromatography)

Typical gas pipe subjected to sulphide gas concentration

Com

po

nen

t A

nal

ysi

s

Gas chromatograph

Perkin Elemer 8700

The Cambridge Thomas Gas Calorimeter

The honeywall heating value transmitter (HVT)

Specific gravity bell

The British Gas Reference Calorimeter

Den

sity

Mea

sure

men

t

Spinner Type

Vibrating Element

Buoyant Beam

British Gas Density Balance

Ac-Me Balance

Debro recorder

Wobbe Number Measurement

Wobbe number is simply an indicator of the quality of a fuel gas, quantified from

the heat produced by burning through a defined orifice under standard

temperature and pressure conditions, quantitatively defied as the ratio of Btu per

cubic Foot to the square root of the specific gravity of the gas.

Dr Nasr, G. G. & Mr Connor, N. E. (n. d). Experimental & Measurement Methods (Module 4). School of Computing, Science & Engineering.

Nasr, G. G. & Connor, N. E. (n. d.). Natural Gas Engineering and Safety Challenges: Downstream Process, Analysis, Utilization and Safety

Siti, N. L. (2012). The Electric Iron. Retrieved from https://2r7science2012.wordpress.com/2012/07/02/the-electric-iron/

Filled Bulb Temperature Sensors. Retrieved from http://www.instrumentationtoolbox.com/2011/01/sensors-used-in-industrial_26.html#axzz3U4AkQ86q

REFERENCES

Keller M. S. R.: Infrared Thermometer Solutions (n. d.).

Temperature At A Rolling Stand.

Wika Instruments, LP. (2014). Pressure-Sensor Fundamentals:

Interpreting Accuracy and Error. Retrieved from http://en-

co.wika.de/upload/TA_0614_CEP_en_co_59242.pdf

RDP Electronics Ltd. (2005). White Paper 1: Understanding

Transducer Characteristics and Performance. Retrieved from

http://www.technicalmarketingltd.com/VNO/RDP/downloads/Whit

ePaper001.pdf

D. V. S. Murty. (2010). Transducers and Instrumentation (2nd ed.).

Retrieved from: https://books.google.co.uk

Thank you for your

attention