B.Raveender Singh

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LEVEL MEASUREMENT
BY, B.Raveender Singh
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• CONTENTS
• Classification of level system
• Brief introduction to the methods
• Level switches
• Summary

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Classification of Level Measurement Systems
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Classification of Mechanical Level Measurement
Systems
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GAUGE GLASS

• Simplest of level indication
• Direct level indication
• For local display
• Can also be used for closed/pressurized tanks

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Float Type Level Measurement

• Used mainly for open tanks local level
  indication.
• Float and tape method is widely used.
• Spherical floats are preferred .
• Magnetic bond type ball float .

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Displacer Type
Principle of operation Works on
Archimedes Principle of Buoyancy It
states that the resultant force of a fluid on a
body immersed in it acts vertically upwards,which
is equal to the weight of the liquid displaced.
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Theory
Buoyancy Force F (Vx Phg) (V-Vx )PL g V
Displacer volume Vx Volume of medium
displaced by displacer Ph Average density of
heavier medium. PL -- Average density of lighter
medium. Fg -- Displacer body weight.
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Displacer Type

• Commercially named as Level Trol.
• Torque tube forms the main transducting element.
• Torque developed is converted to standard signal
  and transmitted to control room.

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Displacer Type

• Mainly used for remote level indication and
  control
• Simple reliable and accurate.
• Can be used for liquids which tends to solidify
  under atmospheric conditions.
• Can be used at very high temperatures and
  pressures.

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Hydrostatic Type
Hydrostatic head is the force due to liquid
weight above the reference line .It is exerted
equally in all directions and independent of
volume or shape of the vessel.
Pressure P p g h P density
h