Emerson 5301HxxxxxxxxxxxxxxZZ Series Reference Manual page 24

Transmitter overview
April 2019
2.7.6 Interface level measurement
Rosemount 5302 is the ideal choice for measuring the level of oil, and the interface of oil
and water, or other liquids with significant dielectric differences. Rosemount 5301 can
also be used for interface measurement in applications where the probe is fully submerged
in the liquid.
Figure 2-8: Interface Level Measurement
A. Rosemount 5302
B. Rosemount 5301
C. Rosemount 5302 with large coaxial probe
D. Product level
E. Interface level
F. Product level and interface level
G. Interface level with submerged probe
H. Product level and interface level with submerged probe
All probes can be used for measuring interfaces. Single probes are the preferred choice in
almost all applications but depending on the application and installation geometries a
coaxial probe or a twin probe may be a better fit.
For measuring the interface level, the transmitter uses the residual wave of the first
reflection. Part of the wave, which was not reflected at the upper product surface,
continues until it is reflected at the lower product surface. The speed of this wave depends
fully on the dielectric constant of the upper product.
The maximum allowable upper product thickness/measuring range is primarily
determined by the dielectric constants of the two liquids. Target applications include
interfaces between oil/oil-like and water/water-like liquids. For such applications the upper
product dielectric constant is low (<3) and the lower product dielectric constant is high
(>20).
24
Reference Manual
00809-0100-4530
Rosemount 5300 Level Transmitter