Ponsel ACTEON 5000 - PHEHT Sensor Maintenance

50
Version 2.1
Update: April 2016
PONSEL Mesure – Aqualabo Contrôle
35 Rue Michel Marion – 56850 CAUDAN, FRANCE
Tel.: +33(0)2 97 89 25 30 – Fax: +33(0)2 97 76 55 72
7.2.3 PHEHT sensor: pH/Temperature.
General description
pH/Redox: Potentiometric measurement;
pH: a pair of electrodes; a reference (Ag/AgCl gel) and a glass bulb sensitive to H
3
O
+
ions
Redox: a pair of electrodes; a reference (Ag/AgCl gel) and a platinum disk
Temperature: NTC thermistor.
Materials
Glass, platinum, PVC, POM-C, Polyamide, Stainless steel 316L (sleeve protecting
the temperature sensor); polyurethane sleeve on cable.
Precautions
The glass electrode is sensitive to:
- chemicals (organic solvents, strong acids and bases, hydrogen peroxide,
hydrocarbons),
- mechanical stresses (impacts).
The electrode that measures the Redox potential is sensitive to sulfides, which are
adsorbed onto the platinum.
Measurement/Interference
When immersing the sensor in the medium to be measured, wait until the sensor's
temperature has stabilized before taking the reading.
Operating temperature
0 °C to 50 °C
Servicing
After each use, rinse the sensor carefully in clean water.
pH: If deposits such as biofilm or sludge persist, immerse the sensor in a cleaning
solution (PF-CSO-C-00010) for a few hours and rinse with plenty of water before
use.
Do not use a soft cloth or absorbent paper since the glass bulb is extremely sensitive
to scratching.
Redox: clean the platinum disk using fine, wet abrasive paper (such as P1200 or
P220).
Storage
Keep the glass membrane hydrated by adding a few drops of storage solution (PF-
CSO-C-00005) to the protective bag, or using a solution at pH 4. Rinse the glass
bulb with plenty of water before use. If the sensor is stored in dry conditions, soak
the sensor in a pH4 buffer solution for 12 hours before use.
The protective bag absorbs direct impacts on the head of the sensor.
The platinum electrode is kept under dry conditions.
Storage temperature
0 °C to + 60 °C
pH calibration
Using a clean sensor, perform a 2-point calibration of the sensor (offset and gain,
e.g. at pH7 and pH4).
Redox verification
Using a clean sensor, check the electronic 0 by exposing the sensor to air, and
check a second point using a buffer solution at 240 mV (or 470 mV).
Temperature calibration
Refer to section 7.2.1
Changing the cartridge
In order not to damage the electronic part of the sensor, hold the cartridge in one
hand and unscrew the connecting ring using the other hand. Remove the used
cartridge and insert the new cartridge before re-tightening the connecting ring.