Test Procedure - Elcometer 138 Guia Del Usuario

3 TEST PROCEDURE: ASTM D4940 (continued)

3.3 TEST PROCEDURE

1 Measure out 300ml of abrasive in the 600ml glass beaker then
add 300ml of pure water.
2 Stir the solution for one minute using the stirring rod. Leave to
stand for 8 minutes, then stir again for a further one minute.
3 Insert a filter paper into the funnel and filter a sufficient amount of
the solution into the 100ml glass beaker, discarding the first 10ml
of filtrate.
4 Rinse the Elcometer 138E Conductivity Meter sensor cell with pure
water until tests show the rinse water has a conductivity of 5µS/cm
or less, see Section 4.9 on page en-14.
5 Measure the conductivity of the solution using the Elcometer
138E Conductivity Meter, see Section 4.9 on page en-14.
Rinse the sensor cell several times with the solution to be measured before

taking the reading.
6 Measure the conductivity of successive portions of the solution
until a constant value is obtained.
3.4 CALCULATE THE CONDUCTIVITY OF THE ABRASIVE (C )
Calculate the specific conductivity of the abrasive (C ) using the
following formula:
C = C x K
s m
where:
C = specific conductivity of the abrasive
s
C = measured conductivity of abrasive / pure water solution
m
K = conductivity cell constant, see Section 3.2 on page en-3.
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3.5 AFTER TEST
Rinse all components of the test kit in pure water. They can then be
re-used.
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Stir: 1 Min
Stand: 8 Min
Stir: 1 Min
s
s
en-4
R