palintest Micro 600 - 6 Probe Maintenance; Cap and Electrolyte Replacement

6
Probe Maintenance
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6.0 Probe Maintenance
The Micro 600 DO probe is a galvanic measuring element which produces an
output proportional to the oxygen present in the medium in which it is placed.
The galvanic probe design lets you take measurements immediately - without
the typical 15 minute wait of polargraphic dissolved oxygen probes.
The probe consists of two parts. The upper part consists of the anode, cathode, and
dual cable. The lower part consists of a pre-assembled cap, and electrolyte solution.
Oxygen diffuses through the membrane onto the cathode, where it is consumed.
This process produces an electrical current which flows through the cable to the
meter. The electric current produced is proportional to the oxygen that passes
through the membrane and the layer of electrolyte. This makes it possible to
measure the partial pressure of oxygen in the sample at a given temperature.
Since the DO in the sample is consumed by the cathode it is essential to have
flow past the membrane of the probe to prevent the occurrence of false readings.
The probe uses very little oxygen for its measurement. This enables it to function
correctly with liquid movement as low as 2 inch/sec across membrane.
The permeability of the membrane to oxygen varies greatly with temperature.
Therefore compensation is needed for this variation. The Micro 600 DO probe
comes with built-in temperature compensation for the membrane variation.
Proper maintenance will help you maximise probe life and accurate readings.
Deposits on the membrane surface act as a barrier to oxygen diffusing
through the membrane, so clean the membrane to assure maximum reliability.
After each use, rinse the probe with clean water to avoid any hardening of
deposits. If growth develops on the probe, use a disinfecting chemical to clean.
NOTE: Although the membrane is strong and not easily damaged,
wipe it gently while cleaning it. If the membrane is punctured,
damaged, or torn, the probe will not function properly.
There are no special probe storage requirements.
6.1 Cap and Electrolyte Replacement
Replacement of the pre-assembled cap is required only when you cannot
calibrate the probe, or if the membrane is damaged. Typical membrane
damages are punctures or wrinkles caused during measurements or cleaning.
Micro600DO_ZI INST 1240 16/9/15 12:57 Page 28