Electrodes; Electrode Holders; Electrode Cleaning And Maintenance; Reconditioning - Etatron HD-PH Instrucciones

9.0 E
LECTRODES
9.1 E
LECTRODE HOLDERS
Three different types of electrode holders are available: monotubular for immer-
sion, electrode cell, and for direct insertion in piping. It is essential to bear in mind
that the distance between the injection point and the electrode must never be less
than one metre. When this is not possible, an appropriate mixer must be inserted
between the injection point and the electrode.
9.2 E
LECTRODE CLEANING AND MAINTENANCE
When the electrode is not used for a lengthy period of time, it is important to pre-
serve it immersed in a 3 M potassium chloride (KCl) solution. The formation of
deposits on the electrode will produce erroneous readings. The necessary cleaning
action depends on the type of deposit under consideration. In the case of thin
deposits, shake the electrode in the manner of a thermometer or use a spray of dis-
tilled water. Organic residues or particularly resistant deposits should be removed
by chemical means. Mechanical cleaning of the bulb should be resorted to only in
extreme cases, but bear in mind that abrasion can lead to irreparable damage. If
cleaning does not fully re-establish the efficacy of the electrode, it may be that the
electrode has aged. Ageing will show itself in the for of either a measurement error
or a slow response. Ageing can be ascertained by thoroughly cleaning the elec-
trode and then measuring a solution of known pH: if the error exceeds 10% (ten
percent), reconditioning will have to be resorted to. If even this fails to re-establish
correct electrode performance, there is no alternative to replacement.
9.3 R
ECONDITIONING
• Immerse the tip of the electrode in 0.1N hydrochloric acid (Hcl) for 15 seconds,
then rinse with water and reimmerse the electrode in a 0.1 N solution of sodium
hydroxide (NaOH) for 15 seconds, followed by a second rinsing. Repeat this
sequence three times, and then carry out another check measurement. If the
check measurement still produces unacceptable measurements, it only remains
to change the electrode.
10.0 M
AINTENANCE
a. Make periodic checks of the level in the tank containing the additive to avoid
the possibility of the pump running empty. Although this will not damage the
pump, level checks are strongly advised to avoid possible damage deriving from
lack of additive in the system.
b. Check the proper functioning of the pump at least once every six months, mak-
ing sure that all screws and gaskets remain tight. Increase the frequency of
these checks when the pump is used to dose particularly aggressive liquids.
c. We would also advise periodic cleaning of the hydraulic parts (valves and filter).
Subject to these general precautions, we would suggest the following maintenance
procedure when the pump is working with sodium hypochlorite (as is often the
case):
a. Stop the pump and detach the delivery hose from the plant.
b. Detach the suction hose with the filter from the storage tank and immerse it in
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