Electro-Chemical Devices (ECD) T80 - Manual (Page 57)

8.3 S80 S
ENSOR
M
AINTENANCE
All electrochemical sensors require periodic cleaning and/or replacement. The life of an electrode is dependent
on the process conditions it is exposed to, a pH electrode may last a year or longer in potable water and only a
few weeks in a hot caustic bath. The chemical constituents in the process may coat the electrode surfaces
requiring the electrode to be removed and cleaned or replaced.
Cleaning agents should be specific to the type of coating, detergents and alcohols for removing greases and oils,
acids for removing hard water scales and metallic deposits or spray washing for flocculants and biofilms.
8.3.1 E
LECTRODE
C
ARTRIDGE
I
NSTALLATION
Unless ordered separately, electrode cartridges are generally shipped installed in a sensor. Sensors ordered
without an electrode are shipped with a shipping plug to keep contamination from getting inside the sensor
during shipment or storage. The following procedure explains how to install the electrode cartridge in the sensor
assembly:
1. Remove the shipping plug by turning it counterclockwise.
2. Remove the electrode cartridge from the protective soaker boot. Be careful not to flex the electrode
body while removing the tape and the protective boot.
3. Rinse the electrode tip in tap water and wipe the electrode body dry then lubricate the o-ring seals with
the included lubricant. Save the protective soaker boot in the event the electrode must be stored at a
future time.
4. Carefully insert the electrode cartridge into the sensor assembly by turning until hand tight. The first o-
ring, closest to the front of the electrode, will be slightly visible if held horizontally.
NOTE: IF EXCESS FORCE IS REQUIRED DURING ELECTRODE INSTALLATION, CHECK FOR PROPER THREAD
ENGAGEMENT OR FOR AN OBSTRUCTION.
8.3.2E
LECTRODE
C
ARTRIDGE
R
EPLACEMENT
Periodic replacement of the electrode cartridge is required for pH, ORP and Specific Ion sensors. The following
procedure explains how to replace the electrode cartridge in the sensor assembly:
1. Remove the electrode cartridge from the front of the sensor assembly by turning it counterclockwise.
2. For installation procedure follow steps 2, 3, and 4 in section 8.3.1 electrode cartridge installation.
8.3.3 E
LECTRODE
C
LEANING
An important aspect of sensor maintenance is the service of the electrode cartridge. After being in operation, an
electrode may begin to exhibit slow response or non-reproducible measurements. This may be due to coating of
the measurement electrode or clogging of the reference junction. Regular electrode cleaning reduces problems
associated with the coating and clogging. Frequency of cleaning will depend on the process and application. The
following procedures are used to clean pH and ORP electrodes.
If possible, the electrode should be cleaned without removing it from the sensor body. However, if the electrode
must be removed, the o-rings must be inspected and re-lubricated. See section 3.10.
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