Briefly description to non-intrusive meters which only explained to magnetic and ultrasonic meters

1. NON-INTRUSIVE
METERS
 MAGNETIC METER
 ULTRASONIC METERS

2. Non intrusive meter
 Principal:
Faraday law of electromagnetic
 Main Parts:
1. Two electrodes for measuring induced
voltage
2. Two coils for generating magnetic field

4.  Working:
• Two coils placed parallel to tube to produce
magnetic field.
• Two electrodes placed right angle to coils.
• When there is no fluid flow, no induced
electrical voltage.
• When fluid flow through magnetic field.
• Conducting fluid distributes its +ve and –ve
ions on electrodes

5. • It generates an electrical voltage which
is measured accurately.
• Electrical voltage is directly proportional
to the velocity of fluid

6.  Advantages and disadvantages
• Depends only on velocity
• Does not depend on viscosity or density
• Measure velocity of almost all liquids
except hydrocarbons(too small electrical
conductivity)

7. HIGH FREQUENCY WAVE
 Two types:
1. Transit time
2. Doppler shift
 Main Parts:
Electronic transducer (for generating
high frequency wave)

8.  Working:
• pair of transducers placed at a certain
angle with tube parallel to each other(one
transducer transmits sound and other
receive sound)
• Initial velocity of wave is known
• If wave is transmitted in the direction of
flow its velocity is increased and vice versa
• From the change in transit time of both
directions, velocity can be determined

9.  Used for only pure fluids

10.  Working:
• Only one transducer is used (act as both
transmit and receiver).
• Pressure wave is projected in the direction
of flow.
• Wave is reflected back due to suspended
particles or bubbles.
• The difference between the frequency of
projected wave and the reflected wave is
proportional to the fluid velocity.

11.  Used for those fluids in which suspended
particles present