Series 8800 – Trace Moisture Analysis Instrumentation
Utilizing an Aluminum Oxide sensor 600 times more sensitive than conventional sensors
The 8800 series uses field proven aluminum oxide (Al2O3) sensing technology to accurately detect trace moisture on either a continuous or spot checking basis.
All Al2O3 sensors share the same basic operating principle: the capacitance measured between the sensor’s aluminum core and gold film deposited on the oxide layer varies with the water content. However, the Series 8800 moisture sensor employs unique Hyper Thin Film (HTF) technology, which offers three major structural improvements in Al2O3 sensor design.
Versatile Design Options
The Series 8800 Single Point Trace Moisture Analyzers are provided in four compact, reliable designs with the ability to detect moisture from -100°C to ambient dewpoint levels of +20°C on either a continuous or spot checking basis.
– 8800A – Flush Mount DIN enclosure with connections made via a pluggable screw terminal block
– 8800B – Wall Mount N4X (IP65) enclosure with connections made 3 bottom watertight fittings
– 8800P – Portable battery operated design available in the Standard Version, I/O Version, and I/S Version (I/S version suitable for hazardous areas)
– 8800T – Low-cost, loop powered 4-20mA transmitter design with built-in LCD display
Common Electronics Platform
The Series 8800 electronics feature a custom LCD 3.5 digit display with backlight capabilities (backlight not available on 8800T). Each controller is operated through a menu-driven user interface. The push buttons or keys have a tactile feel, and to provide additional feedback to the user they also produce a beep when depressed.
Each unit uses a state of the art microprocessor offering advanced intelligent features. In general, the MODE button navigates through the different user options; the UP and DOWN buttons modify the units, values, or choices in the selected mode; and the Pressure Correct button is used to either abort out of a mode or to activate the pressure correction function of the instrument.
The user can select the moisture analysis readout to be displayed as Deg C, Deg F, ppm and for natural gas applications in lbs of H2O/ million cft or g/m3.
Most versions offer the common options of two adjustable alarms, an isolated 0-24mA or 4-20mA output or RS-232C serial interface The instrument also has an indication for sensor open, short or electronic system failure to quickly alert the operator to a possible malfunction situation. In addition, most versions offer extensive self-diagnostic features that are performed at both start-up as well as once every two minutes.
Pressure Correction Function
The moisture readings are typically displayed at sensor pressure (atmospheric). Alternatively, the operator can display the readings at the line pressure by selecting and setting the Pressure Correct Mode key. Readings are typically read on a dewpoint basis in Deg C or Deg F. For readout on a ppm basis, the operator must control / know the line pressure and program this value into the controller via the pressure correct function.
Sensor Installation Considerations
Proper sample handling is crucial to maintaining the tight moisture control demanded by the industry today. Operators can assist in achieving a successful dew point measurement by
• Mounting the sensor as close to the measurement point as possible
• Mounting the instrument as close to the measurement point as practical
Relevant Application Bulletins
– Hydrocarbon processing application: Platformer Recycle Gas moisture measurement – 8800UOP