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© 2014 Spectro Scientific | CONFIDENTIAL
FEBRUARY 2015
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A Practical Alternative to
Karl Fischer Titration for Water
Measurement in Lubricating Oils
© 2014 Spectro Scientific | CONFIDENTIAL
Overview
FluidScan provides
quantitative measurement
of dissolved water, based
upon IR absorbance.
This capability has been
extended and now
measures free water.
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© 2014 Spectro Scientific | CONFIDENTIAL
Water Limits – Industry Best Practices
Recommended water limits for machinery oils are
below saturation levels (dissolved water)
– Typical moisture levels are specified below (ppm)
• Hydraulics 125
• Gearboxes 300
• Paper machines 200
• Steam turbine 100
• Pumps 150
In real world applications, however, free water is
frequently present (water above saturation limit)
The FluidScan Comprehensive Water Solution
measures dissolved and free water.
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© 2014 Spectro Scientific | CONFIDENTIAL
Principle of operation (patent pending)
Free water droplets scatter
IR light, in proportion to the
amount of free water present,
resulting in a vertical shift of
the IR absorbance curves, or
‘baseline shift’.
Extensive Applications
development has quantified
correlations between the
FluidScan baseline shift and
Karl Fischer titration values.
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Comprehensive Water Solution Extended Range
© 2014 Spectro Scientific | CONFIDENTIAL
Measurement Range of FluidScan
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© 2014 Spectro Scientific | CONFIDENTIAL
No Detectable Free Water Detects Free Water
Display of Measured Results
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• Displayed value shows high
Oxidation and TAN, but no free
water.
Displayed value is sum of
dissolved water + free water
Note: Saturation Limit of GST46 <400 ppm
© 2014 Spectro Scientific | CONFIDENTIAL
Oil Categories Covered by Extended Water
Range Algorithm
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Oil Category Extended Water Range
Chiller
Compressor
Gear-splash
Gear-pressure
Hydraulic
Transmission
Turbine Aero
Turbine Steam, CCGT
Engine N/A
© 2014 Spectro Scientific | CONFIDENTIAL
Correlation to Karl Fischer
Plot of 65 samples from
twelve different oil
categories
Correlation to Karl Fischer
Titration = 95.7%
Specified sample
preparation technique
provides good repeatability
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© 2014 Spectro Scientific | CONFIDENTIAL
Sample Preparation Sample preparation is
key to obtaining good
results
If water droplets are not
evenly dispersed in the
oil sample, this can give
misleading results
Homogenizing the
sample gives uniform
and repeatable results
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© 2014 Spectro Scientific | CONFIDENTIAL
Sample Preparation Homogenize sample for 30 seconds
Wait at least 1 minute
Invert bottle 20 times gently
Draw a sample from the center of the bottle
Test with FluidScan
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Homogenized samples
Water separated from oil sample
Benchtop homogenizer
© 2014 Spectro Scientific | CONFIDENTIAL
Requirement for Homogenizer
Must adequately homogenize
sample for meaningful
measurement
Two homogenizer options:
– Table top with stand
– Portable, rechargeable
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© 2014 Spectro Scientific | CONFIDENTIAL
Summary
The Comprehensive Water Solution combines a simple sample
preparation technique and an extended water range library on the
FluidScan to provide a Practical Alternative to Karl Fischer
titration.
The FluidScan is a handheld device that offers a practical solution
for maintaining the key parameters of a healthy lubrication system
without the need for a laboratory. Key measurement parameters
include:
– Water (dissolved and free)
– TAN (total acid number)
– Oxidation
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