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2.1 Sensing element
The sensitive part of the probe is composed of an anode and a cathode, the two elements, constructed
with precious metals, are enclosed in a membrane filled with an electrolyte solution.
The permeable membrane allows the passage of only gas present in the sample to be analysed, blocking
the passage of liquids. The oxygen, after passing through the membrane, reacts with the electrolytic
solution, which changes its chemical and physical properties depending on oxygen concentration. The
sensing elements detect this change and generate a signal in proportion to the amount of dissolved
oxygen. The oximeter reads this signal and returns the value on the display.
2.2 Membrane
The membrane, which must allow only passage of oxygen, must be in perfect conditions.
If it presents any ripples, irregularities or punctured, it must be replaced with a new one.
2.3 Electrolyte
The electrolyte is an alkaline solution that reacts to the presence of oxygen, it saturates with wear and
over time, therefore, it must be replaced regularly.
2.4 Polarization time
The polarographic sensor needs to be polarized prior to making the measurements.
Connect the probe to the instrument and switch on with
button, the device turns on and starts the
countdown for the polarization time. At the end of the countdown the meter enters in measurement mode
and it is ready to make measurements.
The polarization time is 10 minutes. However, if the instrument is turned off for less than an hour, the
polarization time is reduced proportionally.
2.5 New sensor with new instrument
The sensor is supplied with the membrane empty, so it must be filled with electrolyte before using for the
first time. Read carefully the instructions and wait properly for the polarization time.
2.6 Probe storage
When the probe is not in use, store it in the storage tube containing distilled water. In this way, the
membrane remains protected and moisturized, ready for use.
2.7 Not using the sensor for a long period of time: over one month
If the instrument and the sensor are not used for a long period of time (over one month) it is advisable to
empty the membrane from its electrolyte, thoroughly wash the sensor. Dry the sensor and screw the
membrane without the electrolyte to protect the sensor with its rubber cap.
