Emerson Rosemount 5300 Series Product Data Sheet page 25

Product Data Sheet
00813-0100-4530, Rev DA
December 2010
Interface Measurements
Considerations
Solids Measurements
Considerations
The Rosemount 5302 is a good
choice for measuring the
interface of oil and water, or
other liquids with significant
dielectric differences. It is also
possible to measure interfaces
with a Rosemount 5301 in
applications where the probe is
fully submerged in the liquid. If
interface is to be measured,
follow these criteria:
• The dielectric constant
of the upper product
must be known and
should not vary. The
Radar Master software
has a built-in dielectric
constant calculator to
help the user estimate
the upper product dielectric constant
• The dielectric constant of the upper product must have a smaller dielectric constant than the
lower product
• The difference between the dielectric constants for the two products must be larger than 6
• The maximum dielectric constant for the upper product is 8 for the single lead probes, 10 for
the coaxial, and 7 for the twin lead probes
• The upper product thickness must be larger than 5.1 in. (0.13 m) for all probes, except the
HTHP coaxial probe, which requires 8 in. (0.2 m) to distinguish echoes from the two liquids
• Sometimes there is an emulsion layer (mix of the products) between the two products which
can affect interface measurements. For guidelines on emulsion situations, consult your local
Emerson Process Management representative
For information on the maximum allowable product thickness and measuring range, see "Interface
Measuring Range" on page 29.
Rosemount 5303 with a flexible single lead probe is a good choice for measuring solids, such as
powders, granulates, or pellets with a grain size of up to 0.8 in. (20 mm). The measurement is made
where the probe comes in contact with the material, which means that the shape of the material
surface is not critical for the measurement. Measurements are also independent of moisture and
material fluctuations such as density and temperature.
The following should be kept in mind:
• In solid applications, media may cause down-pull forces on silo roofs. The silo roof must be able
to withstand the probe collapse load, or at least the maximum probe tensile load
• The tensile load depends on the silo size, material density, and the friction coefficient. Forces
increase with the buried length, the silo, and probe diameter. In critical cases, such as products
with a risk of build-up, probe for high physical weight loads are available
• Forces on probes, depending on their position, are generally two to ten times greater on probes
with a tie-down than on probes with ballast weights
• For environments where electrostatic discharges (plastics) are likely to occur, grounding of the
probe and vessel may be required
Note:
Abrasive media can wear out the probe, so consider using non-contacting radar.
For more information, refer to the Guided Wave Radar in Solid Level Applications Technical Note
(Document No. 00840-2300-4811).
Rosemount 5300 Series
5302
Level
Interface Level
Interface Measurement with a Rosemount 5302 and a
Rosemount 5301 (fully submerged probe)
5301
Level = Interface Level
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