ACS-CONTROL-SYSTEM
GmbH
l Lauterbachstr. 57 l D-84307 Eggenfelden l www.acs-controlsystem.de l [email protected]4
Application
The device is an electronic hydrostatic lling level transmitter for continuous measuring of lling levels
in liquids within pressure-less container.
The use of a capacitive measuring sensor with ceramic membrane and the corresponding excellent
characteristics, allows the use in nearly all elds of industry.
Optionally the device can be equipped with a process diaphragm seal.
The use of a pressure diaphragm seal with metallic membrane leads to an extension of the application
range of the device.
Pressure diaphragm seals are applied to a measuring device:
• if the process wetted parts, due to the corrosion resistance, must be made of special
materials, that are not suitable for the construction of elastic measuring elements of pressure
measuring devices.
• if measured materials are toxic or ecologically harmful and should not escape into environment
or into the atmosphere, e.g. at leakage of the measuring sensor due to overpressure resp.
wear, and thus, using the pressure diaphragm seal, an additional protection is placed ahead to
the measuring device.
• if the environmental temperature at the measuring place or the temperature of the measured
material it too high for the measuring device and is kept away from it by using a pressure
diaphragm seal with temperature decoupler or capillary line.
• if the installation situation at the measuring place are unsuitable of if mechanical vibrations
and pulsations must be kept away from the measuring device and due to the use of a pressure
diaphragm seal with capillary line the measuring device is mounted away from the measuring
place at a suitable place.
Function
The device is used for lling level measurement by recording the hydrostatic pressure.
The device is mounted in the wall of the container or as a suspend device above the container.
Measuring principle
The height of the liquid column over the measuring membrane causes on the measuring membrane
the so-called hydrostatic pressure, that is dened besides the height of the liquid column also by the
density of the liquid and the gravitational constant.
h = p / (ρ * g)
h >> height (lling level)
p >> pressure
ρ >> density of the liquid
g >> gravitational constant
The hydrostatic pressure of the liquid is applied to the ceramic membrane and causes there a variation
of the capacity at the back side of the membrane.
The ceramic capacitive membrane offers excellent characteristics like highest pressure and pressure
blow strength, vacuum resistance, very high resistance against chemicals, corrosion and abrasion as
well as very good insensitiveness against temperature shocks, highest accuracy and reproducibility,
good long term stability and a very low temperature inuence.
The ceramic capacitive sensor is a dry sensor, that does not need the use of a pressure transmitting
liquid.
Pressure diaphragm seal
The hydrostatic pressure of the liquid is applied to the metallic membrane of the pressure diaphragm
seals and is transmitted by a pressure transmitting liquid to the backside positioned membrane. The
pressure causes there a variation of the capacity at the back side of the membrane.
The metallic membrane offers excellent characteristics like a very high process temperature range,
vibration decoupling as well as an additional process separation.
