Level measurement

10 Continuous level measurement in liquids

1. Overview of the measuring principles

A

Radar

Tank Gauging radar

Guided radar

Ultrasonics

Process temperature Process pressure Measuring range

–196 to +450°C/ –321 to +842°F –1 to +160bar/ –14.5 to +2,320psi

–40 to +200°C/ –40 to +392°F -1 to +40bar/ -14.5 to +580psi

–196 to +450°C/ –321 to +842°F –1 to +400bar/ –14.5 to +5,800psi 0.3 to 45m/1 to 148ft (longer upon request)

–40 to +105°C/ –40 to +221°F +0.7 to +4bar/ +10 to +58psi

0.1 to 80m/0.3 to 262ft 0.8 to 70m/ 2.6 to 230ft

0.07 to 25m/0.2 to 82ft

• ±2 mm/±0.08",

Instrument accuracy

• 6GHz: ±6mm ±0.24" • 26GHz: ±2mm ±0.08" • 80GHz: ±1mm/ ±0.04"

•6GHz:

•

±0.5mm/±0.02"

±0,2 % of distance

•26GHz:

•

±1mm/0.04"

•80GHz:

of distance

±0.5mm/ ±0.02"

Function may be affected by

•Foam • Extreme turbulent surfaces • Conductive build-up on antenna connection • Strong build-up • Wall effects • Interfering reflections/ obstacles in the signal beam • Extreme pressure changes

• Turbulent surfaces •Foam

•Extreme build-up formation

•Foam •Extreme turbulent, boiling surfaces • Strong build-up or strong condensate at the sensor • Higher vapor pressure may change the Time-of-Flight • Temperature layers in the gas phase • Interfering reflections • Fast temperature change • Measurement up to abs. 0% 1 • Vapor pressure • Blocking distance 3 • Lateral installation or from below

Accuracy may be affected by

• Obstacles •Wall effects • Bad stilling well quality

• Interfering

reflections by obstacles near the probe (not for coaxial probe) •Extreme pressure changes •Measurement up to 0% 2 • • Agitator applications • Lateral installation or from below •Extreme foam formation

Application limits

•

• • Measurement up to 0% 2 •Lateral installation or from below

2 Measurement only up to the probe end

1