47
BE 57-660 Eclipse Model 700 Guided Wave Radar Transmitter
Single rod GWR probes are typically the best probes for
applications with potential buildup, but other factors in the
application must be considered (such as mounting, sensitivi-
ty, etc). For this reason, the ECLIPSE Model 700 is offered
with a variety of coaxial and single rod probes, so the cor-
rect probe can be used for the given application.
Refer to Section 3.6.3 for viscosity specifications on the
various ECLIPSE probes.
Contact the factory for any questions regarding
applications with potential coating and buildup.
3.3.5.1 Model 700 (Single Rod Probe)
The Model 700 and Single Rod probe were designed to
operate effectively in the presence of media building up.
Some expected error may be generated based upon the
following factors:
1. Dielectric of the media that created the coating
2. Thickness of the coating
3. Amount (length) of the coating above the present level
Although more immune to thick, viscous, buildup, perfor-
mance of Single Rod GWR probes is always dependent on
the installation and application. The electromagnetic field
surrounding a single rod probe makes it more vulnerable to
influence from objects in the vicinity of the probe.
NOTE: It is important to note that this influence from the
installation/application also depends on the configuration of
the transmitter. Those devices configured with lower gain will
be less affected by external objects.
Nozzles
Due to the impedance mismatch that takes place at the end
of a nozzle, they can create false echoes that can cause diag-
nostic indicators and/or errors in measurement.
As mentioned above, by virtue of the pure physics of the
technology, all single rod GWR probes are influenced by
the application and installation. Mismatches in impedance
along the length of the probe, whether they be expected
(liquid level) or unexpected (metal in close proximity), will
result in reflections.
To better illustrate this, a comparison between a coaxial
probe and single rod probe mounted in the same application
is shown at left.
Process Seal is
Fully Transparent
Coaxial Probe
Large Impedance
Mismatch
Standard Single Rod Probe
Coating
Buildup
¿
¡
➂
Fiducial
Level
Process Seal is
Fully Transparent
Fiducial
Level
Large
Impedance
Mismatch
