Operating instructions

METTLER TOLEDO DE40/50/51 Density Meter 83
Malfunction Cause Measure
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for help.
No key entry Call METTLER TOLEDO service
possible for help.
Measurement Sample not homogeneous, air bubbles Check factors mentioned.
not reproducible in the measuring tube, measurement Check if temperature is stabilized.
temperature unstable. Measurement cell filled completely?
Is the bench vibrating? Place instrument on a non-vibra-
ting bench.
Cell contaminated with old sample. Clean measuring cell thoroughly.
Air bubbles in the Leaking connections? Check connections.
sample i.e. mea- Sample likely to produce bubbles Degass sample (ultrasonic bath or
surement never or mixture containing components heating) or measure at reduced
ends or measuring with low coiling point? temperature.
times vary greatly. High sample viscosity? Use a syringe or warm up the sample.
Long sampling Wrong setting of the flow control Adjust the sampling speed to your
time. valve. sample with the valve.
Sample viscosity too high. Use a syringe to inject the sample.
Measurement of Switch off the instrument and call the
distilled water free METTLER TOLEDO service.
of air bubbles
takes too long.
Adjustment of the Air or gas bubbles are generated by Boil the distilled water, or degass it in
instrument with air the heating-up of the water in the an ultrasonic bath (at least at the
and water at higher measuring cell. measuring temperature), and inject it
temperatures takes at this higher temperature to avoid
too long. formation of air or gas bubbles.
Error messages and malfunctions