Lecture 6

Question 1

Ultra Sonic Flow Meter

Answer 1

GENERAL
- clear amnd dirty liquids in difficult situations
- non-intrusive
- moderate accuracy, highly sensitive
TIME OF FLIGHT
- clear liquid
- time of flight of a high pressure signal from transmitter to reciever
- clamped on outside of pipe
DOPPLER METER
- dirty fluid
- flowrate related to Doppler shif assuming that particles travel t same velocity as fluid

Question 2

Flow Rate Sensors

Answer 2

ORIFICE PLATE
ROTAMETERS
- diffrential pressure method
- linear scale
- clean fluids
TURBINE METER
- clean, lubricating fluids
- wide operating range
- linear signal
ELECTROMAGNETIC FLOWMETER
- no flow restrictions
- must be conducting fluid
- expensive
POSITIVE DISPLACEMENT METERS
- count ‘volume’ packets passing through

Question 3

Pressure Sensors

Answer 3

• Bourdon Tube
• Capsules/Diaghragms
• Slack diaphragm
• Piezoelectric

Question 4

Mass Flowrate Sensor

Answer 4

CORIOLISIS FLOWMETER
- measures mass flowrate directly
- gives simultaneous measurement of fluid density

Question 5

Liquid Level Sensors

Answer 5

• Hydrostatic
• Displacement
• Radiation Absorbtion
• Capacitance/Resistance probe
• Ultrasonic detectors (used for storage vessels)
• Interface detectors
• Load cells (positive measurement of mass of vessel and contents)

Question 6

Temperature Sensors

Answer 6

• Liquid Expansion (leaks can contaminate processs fluid)
• Resistance Thermometer
• Thermocouple
• Probes housed in ‘thermowells’
• Response time constant