BARTEC BENKE HYGROPHIL F 5673, Operating Manual, Page: 7 / 129

System description
1-1
HYGROPHIL® F 5673 Operating manual, Software version 1.8.x, 387896MDHEN(14.06.2013)
1 System description
1.1 Measurement principle, Function
and applications
HYGROPHIL
®
F 5673 is a high-quality, microprocessor-controlled fibre-optic
hygrometer for measuring the moisture or trace humidity at low dew-point
temperatures in gases and liquids.
HYGROPHIL
®
F 5673 works in multi-channel operation with a temperature-
compensated fibre-optic sensor developed especially for measuring the
moisture content in gas mixtures and liquids.
Measurement of water dew point temperature
(Gas humidity)
The water dew point is measured with the HYGROPHIL
®
F and sensor type
L166x.
The moisture sensor,
type L166x, consists of a robust multi-layer of optically
high and low refractive layers connected to 2 fibre-optical cables.
Due to a special thermal coating technique, pores with the diameter of a wa-
ter molecule are generated on the layer.
Due to the moisture equilibrium content, water is deposited in the layer and
changes the refractive index of the irradiating light (air: 1,00/water 1,33).
Within the layer system this results in a wavelength shift in proportion to the
moisture prevailing in the medium.
This shift is measured by the evaluation unit and assigned to a dew point.
The L166x probe makes measurements which are temperature compen-
sated (by the integrated Pt100).
In short, the HYGROPHIL
®
F 5673 works in conjunction with a combination
sensor which fibre-optically determines the moisture content and measures
the temperature in the medium with a Pt100.
Apart from the extremely robust construction of the sensor, it is above all
else, the measurement technique which offers several decisive advantages.
Some of the advantages of this patented measuring method are as follows:
● High measuring confidence, including precision, reproducibility and low
hysteresis.
● Long-term stability of the sensor (no drift!)
● Measurement is possible on the high-pressure side (pressure dew point!)
● Application in explosive areas (zone 0 and higher)
● Simple installation and upgrading (Swagelok, Parker, …)
The L166x was developed especially for natural gas applications and is now
applied in trace moisture measurement for a large number of different gases
and liquids.
Due to the usage of high-quality materials, the sensor is extremely robust
and resistant to most media.