Level Tables Disadvantages

Question 1

Blocking distance

Answer 1

Ultrasonic, Radar, Guided Wave Radar

Question 2

Turbulent surfaces

Answer 2

Ultrasonic, Radar, Guided Wave Radar

Question 3

Minimum dielectric constant

Answer 3

Radar & Guided Wave Radar

Question 4

Foam is an issue

Answer 4

Ultrasonic

Question 5

Foam can be an issue

Answer 5

Radar & Capacitance Level Measurement

Question 6

Vapors/gas above the liquid

Answer 6

Ultrasonic

Question 7

Temperature difference between liquid and sensor

Answer 7

Ultrasonic

Question 8

No vacuum (10 psia), no high pressures (44 psia)

Answer 8

Ultrasonic

Question 9

Minimum density required

Answer 9

Ultrasonic

Question 10

Must take into account tank design

Answer 10

Radar & Guided Wave Radar

Question 11

Minimum dielectric constant

Answer 11

Radar & Guided Wave Radar

Question 12

Heavy foam can be an issue

Answer 12

Guided Wave Radar

Question 13

Many versions (conductor/insulator)

Answer 13

Capacitance Level Measurement

Question 14

Probe coating (chemical compatibility)

Answer 14

Capacitance Level Measurement

Question 15

Ground reference tube (non-metallic)

Answer 15

Capacitance Level Measurement

Question 16

Re-calibration with different media

Answer 16

Capacitance Level Measurement

Question 17

10 pF minimum span

Answer 17

Capacitance Level Measurement

Question 18

Most expensive level device

Answer 18

Radiometric (gamma) Level Measurement

Question 19

Requires extra documentation and paperwork (swipe tests)

Answer 19

Radiometric (gamma) Level Measurement

Question 20

Dependent on country-specific regulations

Answer 20

Radiometric (gamma) Level Measurement

Question 21

Maintenance (mechanical, and have moving parts)

Answer 21

Floats

Question 22

Inaccuracy due to coating/buildup (float may stick, too much buildup can effect set point)

Answer 22

Floats

Question 23

Corrosion of float (ex: holes)

Answer 23

Floats

Question 24

Passive system (won’t know if float sticks)

Answer 24

Floats

Question 25

Sensitive to foam/air bubbles

Answer 25

Ultrasonic Gap Switches

Question 26

Coating/buildup can cause failure to sense liquid level (solids or coating can result in device malfunction)

Answer 26

Ultrasonic Gap Switches

Question 27

Calibration for specific liquid (being measured)

Answer 27

Thermal Dispersion Switches

Question 28

Slow speed response

Answer 28

Thermal Dispersion Switches

Question 29

Coating can be an issue (effect proper operation)

Answer 29

Thermal Dispersion Switches

Question 30

Buildup/coating an issue (can change resistance)

Answer 30

Conductivity Point Switches

Question 31

Calibration needed (frequently)

Answer 31

Conductivity Point Switches

Question 32

Conductive liquids only

Answer 32

Conductivity Point Switches

Question 33

Not as well-known as the others

Answer 33

Vibrating Fork Point Switches

Question 34

Too much buildup on one time (failsafe mode)

Answer 34

Vibrating Fork Point Switches