Elimination Of Temperature Effects; Calibration - Michell Instruments Liquidew EExd User Manual

Liquidew EExd User's Manual
Four user-programmable tables enable the Liquidew EExd to be applied to virtually any
immiscible solute. For simple mixtures of hydrocarbons, a proportional combination
of the Cs values for two or three individual substances can be applied, although with
increased measurement uncertainty. For applications with complex mixture fluids,
customers can enter their own Cs values (in ppm
(+32 to +122°F)) from their own library sources or from actual laboratory titration
analysis of the fluid concerned.
1.7

Elimination of Temperature Effects

To ensure continuous optimum analysis conditions the Liquidew EExd Main Unit is
temperature controlled (internally) at a stable level. The control temperature level is
selected to suit the climate at the point of installation, being set to the normal maximum
temperature. Such steady state control within the analyzer greatly reduces the effects of
diurnal (day-night) swings in temperature. These temperature changes could otherwise
induce transitional adsorption and desorption effects of the flowing sample and result
in erroneous measurements.
In addition, the Liquidew EExd features an advanced temperature compensation
algorithm that automatically maintains best possible measurement accuracy in the
event of heater failure or if the prevailing climate exceeds the set temperature level.
1.8

Calibration

Maintenance of calibration is essential to the lifetime performance of all analyzers. To
ensure that all customers worldwide can maintain the performance of their Liquidew
EExd, the unique Michell Calibration Exchange Service offers freshly calibrated
replacement Ceramic Sensors certified traceable to NPL and NIST. The calibration
characterization data for each Liquidew EExd Sensor is programmed into on-board
non-volatile memory. Fitting the Calibration Exchange Sensor refreshes the calibration,
returning the measurement performance to day-one. This takes only a few minutes of
downtime while the interchange is made. No programming or data input is required by
the user to complete this.
The calibration exchange is available globally, typically taking less than two weeks, with
comparable cost of a traditional 'return to manufacturer' re-calibration service.
The recommended calibration maintenance interval is 12 months.
Michell Instruments
INTRODUCTION
for temperatures from 0 to +50°C
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