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Replatinising Conductivity Sensors
There are several ways to replatinise Conductivity electrodes.
1.
The simplest way is to return the electrode to the TPS factory. We can fully clean the electrode,
replatinise it and test all aspects of its performance.
2.
An automatic replatiniser is available from TPS, along with replatinising solution. This will
plate the electrodes for the right amount of time at the correct current. Ordering details are as
follows…
Automatic Conductivity Electrode Replatiniser
Part No 122160
20mL Platinising Solution (suitable for approx 30 uses)
Part No 122300
3.
Conductivity electrodes can be manually replatinised, according to the following procedure…
(a)
Soak the electrode in a solution of 1 part Concentrated HCl and 10 parts distilled water for
approximately 5 minutes.
(b)
Rinse the electrode well in distilled water.
(c)
Immerse the electrode in platinising solution at least to the vent hole in the body.
Platinising solution is available from TPS (part no 122300). Alternatively, platinising
solution can be prepared by dissolving 1g of Hydrogen Chloroplatinate (H
2
PtCl
16
) in 30mL
of distilled water, and including about 0.01g of Lead Acetate ((CH
3
COO)
2
Pb) and a drop
or two of concentrated HCl.
Caution : This is a dangerous solution and should be
handled with the utmost care.
(d)
Apply a direct current of 10mA between pins 7 and 8 of the electrode plug, as per the
diagram below. Reverse the polarity every 30 seconds. After approximately 8 minutes (4
minutes per electrode plate), they should have an even “sooty” appearance. Avoid excess
current as this will cause incorrect platinising.
(e)
After platinising, rinse the electrode well in distilled water.
(f)
If you have any doubts about any of these steps, then you should consider returning the
electrode to the factory. The cost of replatinising is quite low, and you will be guaranteed
of the best possible result.
Pin 8
Pin 7
Sensor Connector