Saab TankRadar Rex

Technical Description
10
Accuracy enhancement
To enhance accuracy further, TankRadar Rex has
some built-in unique features:
Temperature control
TankRadar Rex gauges are designed to operate in
all climates. The gauge is continuously controlling
the temperature of the electronics and keeps it
constant. This is one of the reasons for the high
accuracy and the 65 years of mean time between
failure (MTBF) for the gauge.
Digital reference
A radar gauge needs an internal reference to make
the radar sweep absolutely linear. Each deviation
from the linearity produces a corresponding
inaccuracy. To achieve highest precision, Saab
TankRadar Rex uses a digital crystal oscillator. This
gives the most stable reference that is available with
today’s technology.
Drip-off means no condensation
If the antenna has an inclined polished PTFEsurface
(Teflon ® ) where the microwaves are emitted,
it will be less susceptible to condensed water or
product. The drops of condensation will not coat
the active part of the antenna. In this way the radar
signal will be less weakened resulting in higher
accuracy and better reliability.
Measurement close to tank wall
A standard manway (or flange) is normally 0.3-1 m
(1-3 feet) from the tank wall. Both the Saab RTG
3920 Horn Antenna Gauge and the RTG 3930
Parabolic Antenna Gauge are specially designed to
be mounted close to the wall.
The RTG 3920 Horn Antenna Gauge radar signal is
polarized so that the direct reflection from the
liquid surface is the only detectable reflection. Any
wall disturbance will be blanked out. The RTG 3930
Parabolic Antenna has a narrow radar beam due to
the large 20-inch antenna diameter resulting in a
small and uncritical wall echo.
Antenna design with no horizontal surfaces according to the American
Petroleum Institute Standard (API ch. 3.1B).
Tank
wall
Not
accepted
Tank
wall
Liquid Liquid
Accepted
Gauges emitting microwaves with circular polarization can be installed
closer to the tank wall.