VEGA VEGAFLEX 86 Foundation Fieldbus Coax probe - Manual (Page 17)

17
4 Mounting
VEGAFLEX 86 • Foundation Fieldbus
44230-EN-130910
The reference plane for the measuring range of the sensors is the
sealing surface of the thread or flange.
Keep in mind that a min. distance must be maintained below the refer-
ence plane and possibly also at the end of the probe - measurement
in these areas is not possible (dead band). These dead bands are
listed in chapter "Technical data". Keep in mind for the adjustment that
the default setting for the measuring range refers to water.
The process fitting must be sealed if there is gauge or low pressure in
the vessel. Before use, check if the seal material is resistant against
the measured product and the process temperature.
The max. permissible pressure is specified in chapter "Technical
data" or on the type label of the sensor.
Instruments for a temperature range up to 280 °C or up to 450 °C
have a distance piece between process fitting and electronics hous-
ing. Ths distance piece is used for thermal decoupling of the electron-
ics against high process temperatures.
Information:
The distance piece must only be incorporated up to max. 50 mm (2 in)
in the vessel isolation. Only then, a reliable temperature decoupling is
guaranteed.
1
2
Fig. 8: Mounting the instrument on insulated vessels.
1 Temperature insulation
2 Ambient temperature on the housing
Vapours, superimposed gases, high pressures and temperature dif-
ferences can change the spreading speed of radar impulses.
There are two possibilities to correct these deviations.
Measuring range
Pressure
Mounting in the vessel
insulation
Steam boiler applications