Level measurement

Instrument selection within the measuring principle

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Vapor pressure of the medium (20°C/68°F) The vapor pressure of the medium at 20°C/68°F is an indication for the accuracy of ultrasonic level measurement. If the vapor pressure at 20°C/68°F is lower than 50mbar/0.73psi, ultrasonic measurement is recommended. If the vapor pressure at 20°C/68°F is above 50mbar/0.73psi, the accuracy of the measurement will be affected. To achieve the highest accuracy results, radar level measurement is recommended.

Advantages • Non-contact, maintenance-free measurement • etc. • Calibration without filling or discharging • Self-cleaning effect due to vibrating sensor diaphragm

Vapor pressure

Examples

Water, water solutions, water-solids solutions, dilute acids (hydrochloric

C

(20°C/68°F)

(20°C/68°F)

Range calculation and selection of sensor for Prosonic M FMU4x and FMU30

Example (for FMU41): • Very turbulent surface: 20dB • medium surface approx. 60°C/140°F: 15dB • Total: 35dB range approx. 6m/20ft

R[m/ft]

20/65

FMU44

10/32

FMU42

8/26

FMU41

Example (for FMU30 2" sensor): • Strong turbulence surface:

5/16 6/20

approx. 20dB

FMU40

• No dust formation: • Filling curtain in detection range:

0dB

1/3.2

10dB

10 20 30 40 50 60 70 80 A [dB]

Total: approx. 30dB range approx. 7.8m/26ft from diagram