A Stable Signal Over a Long Range
Due to the high resistance of the glass
membrane, conventional electrodes require a high impedance measurement system.
Inadequate insulation of the connectors and cables result in erroneous
readings due to leakage or noise. For conventional electrodes, the lead is
therefore limited to typically less than 15- 20 meters. HANNA AmpHel®
electrodes incorporate a miniaturized amplifier which resolves most of the
problems associated with high impedance signals. The amplifier circuitry is
located right on top of the electrode and is completely sealed. As a result, a
strong, low impedance signal is emitted and ordinary connectors with long
unshielded cables can be used. This breakthrough technology provides a stable
signal for industrial monitoring as well as a major saving in low noise
coaxial cable costs. In some cases, the need for a transmitter is also
eliminated, resulting in further cost reductions.
For those applications that have proven
particularly hostile to electrodes, HANNA has developed four types of
specialized glass. First is an extremely durable sensor glass for general
purpose, industrial use. This glass can withstand the stress of daily use. The
remaining types of electrode glass allow continuous monitoring in highly
acidic solutions containing fluoride ions, as well as high or low temperature
process streams, without significantly reducing the useful life of the
Electrode body material is glass or PEI, while
the junction is cloth or PTFE.
Easy installation of these electrodes is
possible thanks to the ¾" UNF external thread. Models with glass body
and PTFE junctions are recommended for in-line installations. Models with an
PEI body and cloth junction are suitable for tank monitoring or for use with
portable meters, where the electrode can be easily accessed for maintenance.