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MARCH 2014

GRADUATE SHARING SESSION

INSTRUMENTS FOR MEASUREMENT ANDCONTROL

Name: Ong Jit Choon

Department: Instrumentation, Control, and Telecommunication

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INTRODUCTION

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4 main categories:Pressure

Temperature

Level

Flow

Selection of ranges: 50% - 75%

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Pressure Instruments

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Bourdon tube

http://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-

gauge-principle.html

Operating principle:

- Pressure to open end

- Displacement of free end

- Pinion rotation

Applications:

- Medium to high pressures

- Inexpensive

- Highly automated chemical

processes

- Installations

http://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.htmlhttp://yourinstrumentation.blogspot.com/2011/10/bourdons-tube-pressure-gauge-principle.html

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Pressure Instruments (cont)

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Helical

www.instrumentationtoolbox.com

Operation principle:

- Uses bourdon tube principle

- Increase tip travel tip motion

Applications:High pressure processes

http://feedburner.google.com/http://feedburner.google.com/

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Pressure Instruments (cont)

Diaphragm

5

http://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-

operating.html

Operation principle:

- Diaphragm seal

- Hydraulically generate

pressure reading

Applications:

- Protect pressure sensor

- High sensitivity

http://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://forbergscientific.blogspot.com/2011/09/diaphragm-seal-chemical-seal-operating.htmlhttp://1.bp.blogspot.com/--oaZKfv6oQk/TnyhKU8eKMI/AAAAAAAAAIM/DIoU9hT1R0k/s1600/Wika-pressure-gauge-&-diaph.jpg

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Temperature Instruments

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Dial thermometer

Google image

http://home.howstuffworks.com/therm2.htm

Operation principle:

- Heat bimetallic strip

- Expansion

- Heat is proportional to the

movement of the dial

Applications:

- Installed where operator

actions are needed

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Temperature Instruments (cont)

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Thermocouple

http://en.wikipedia.org/wiki/Thermocouple

Operation principle:

- Electric current due to difference

in temperature

- Potential difference to temperature

table

Applications:

- High temperature (furnace, refinery)

- Sulfur compounds

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Temperature Instruments (cont)

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Resistant thermometer

Thin filmWire woundCoil element

- Sensing element

- Coated with epoxy or glass

- Not stable

- Limited temperature ranges

- Sensing wire wrapped around core

- Connected to element lead

- Higher accuracy

- Wider temperature ranges

- Strain free

- Hard ceramic oxide housing

- Widest temperature ranges

www.wikipedia.com

http://en.wikipedia.org/wiki/File:Coil_Element_PRT.pnghttp://en.wikipedia.org/wiki/File:Wire_Wound_PRT.pnghttp://en.wikipedia.org/wiki/File:Thin_Film_PRT.png

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Level Instruments

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Differential-pressure level instrument

http://www.gilsoneng.com/reference/Levelpap.pdf

Operation principle:

- Measure head pressure

- Multiply with density

- Resultant force

Applications:

- Most frequently used device

- Readily installed

http://www.gilsoneng.com/reference/Levelpap.pdfhttp://www.gilsoneng.com/reference/Levelpap.pdf

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Level Instruments (cont)

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Displacer level instrument

http://www.gilsoneng.com/reference/Levelpap.pdf

Operation principle:

- Archimedes principle

- Change in level change in

displacer weight

Applications:

- Accurate

- Adaptable to wide variations

in densities

- Slurries and interfaces services

http://www.gilsoneng.com/reference/Levelpap.pdfhttp://www.gilsoneng.com/reference/Levelpap.pdf

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Level Instruments (cont)

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Radar type instrument

http://www.gilsoneng.com/reference/Levelpap.pdf

Operation principle:

- Microwave pulse

- Time of flight = level

- Build profiles of echoes

Applications:

- Accurate

- Expensive

- Ignores vapors and immune to

most physical characteristics

- Liquids and slurries services

- Maybe in granular services

http://www.gilsoneng.com/reference/Levelpap.pdfhttp://www.gilsoneng.com/reference/Levelpap.pdf

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Flow Instruments

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Vortex flow meter

http://www.instrumart.com/pages/230/vortex-shedding-flow-meters

Operation principle:

- Obstruction by bluff

- Increase in pressure, decrease in

velocity- Frequency = velocity

- Sensor

Applications:

- Most preferred

- Low sensitivity to variations- Low cost

- Maybe for dirty fluid

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Flow Instruments (cont)

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Turbine meter

http://www.instrumart.com/pages/227/in-line-turbine-paddle-wheel-flow-meters

Operation principle:

- Reduce turbulent flow

- Spin rotor blade which produces

a signal- Signal is proportional to the flow

rate

Applications:

- Liquids and gases processes

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Flow Instruments (cont)

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Positive displacement meter

http://www.instrumart.com/pages/224/positive-displacement-flow-meters

Operation principle:

- Pressure to cause rotation of gears

- Entrance of fluid at B and removalof fluid at A

- Flow rate is proportional to the

rotational speed of gears

Applications:

- Clean process fluid- Not for slurries or abrasive liquids

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Flow Instruments (cont)

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Coriolis flow meter

www.omega.com

Operation principle:

- Oscillating measuring tubes

- Resultant phase shift = rate of

mass flow

Applications:

- Detection of all liquids

- Sanitary applications

- Continuous tube slurry services,

multi-phase fluid applications,clogging fluids

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Flow Instruments (cont)

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Ultrasonic flow meter

www.omega.com

Operation principle:

- 2 sensors measure transit time

difference

- Directly proportional to the flow

velocity

Applications:

- Wastewater (dirty liquids) applications

- Not for distilled/drinking water

- Low pressure drop, chemical

compatibility, and low maintenance

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Conclusion

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Main categories in measurement and controlinstrumentation

- Pressure

- Temperature

- Level

- Flow

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THANK YOU

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Graduate Sharing Session