Hydrocont K
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Application
The device
Hydrocont K
with integrated analogue evaluation electronic is a compact transmitter for continuous
measuring of fill levels and temperatures in liquids at hydrostatic pressures from -1 up to 20 bar within pressure
less container, also in explosive hazardous areas, at process temperatures from – 20°C to +140°C.
The use of a capacitive measuring sensor with ceramic membrane, allows the use in nearly all fields of industry,
especially in hygienic applications.
Application fields are e.g. water, waste water, solvents, oil, sludge, fat, cleaning liquids, etc.
By using suitable materials like PEEK, FEP or also FFKM, the device can also be used at applications with
especially aggressive liquids.
Function
The device
Hydrocont K
is sunken down into the liquid by the carrying cable or mounted by the respective
process connection into the wall of the container or pipe
Measuring principle
The device
Hydrocont B
is used for filling level measurement by measuring the hydrostatic pressure.
The height of the liquid column over the measuring membrane causes on the measuring membrane the
so-called hydrostatic pressure, that is defined besides the height of the liquid column also by the density of the
liquid and the gravitational constant.
g
p
h
with
Characteristics of the ceramic measuring membrane
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.
A pressure transmitting liquid is not used.
The ceramic membrane offers excellent characteristics like highest pressure and pressure blow strength up to
eighty times the nominal pressure, 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 influence.
Characteristics of the process diaphragm seal – high temperature variant – type H
The hydrostatic pressure of the liquid is applied to the metallic membrane of the process diaphragm seal and is
transmitted by a pressure transmitting liquid to the ceramic measuring membrane that is placed behind.
This leads among others to a extension of the permissible medium temperature up to +140°C.
Signal processing
The filling level proportional hydrostatic pressure signal of the ceramic membrane is measured by the integrated
analogue electronic and converted in a output current signal of 4…20mA.
The measuring signal range can be adjusted corresponding to the requirements of the application in a wide
range for measuring range zero and end value.
Furthermore an influence of the measuring signal by an adjustable damping for neutralization of short pressure
blows or also for calming down cyclic fluctuating pressure signals is possible.
Integrated over voltage protection components prevents the filling level sensor from destruction by atmospheric
influences like e.g. thunderstrike.
h height (filling level)
p pressure
density of the liquid
g gravitational constant
