Yokogawa DO30G Dissolved Oxygen Sensor - Manual (Page 22)

<4. Maintenance>
4-5
IM 12J5B3-01E
Table 4.1 Items Contained in the DOX8A Maintenance Parts Kit
Item Part No. Qty Remarks
Electrolyte K9171DN 50 ml
Must be replaced periodically, either once every 6 to 8
months or if a span adjustment is not possible. Eight to 9
ml are consumed with each replacement.
Permeable-membrane
assembly / O-ring
K9171HM 3 sets
Normally, these parts must be replaced at the same time
that the sensor is refilled with electrolyte. If the sen-
sor is used in a slurry solution, these parts may require
replacement more often due to abrasion or damage.
Reagent for preparing calibra-
tion solution (for zero adjust-
ment)
sodium sulfite (Na
2
SO
3
)
L9920BR 500 g
Calibration must be carried out at a predetermined
interval (the frequency of calibration varies depending
on the operating conditions). Calibration must also be
performed when, for example, the electrolyte is replaced.
Approximately 15 grams of the reagent is needed to pre-
pare 1 liter of the calibration solution for zero adjustment.
5-ml syringe (without needle)
Needle
L9827NH
L9827NG
1
1
Used when replacing the electrolyte.
200-ml beaker L9825AF 1
Used when calibration is carried out or when the electro-
lyte is replaced.
Abrasive for silver electrode
(alumina)
K9088PE 30 g
When the permeable-membrane assembly is replaced,
the silver electrode must be polished until it becomes
glossy. Only an extremely marginal amount (approx. 0.5
mg) of the abrasive is consumed with each polishing.
4.3.2 Parts That Should Be Kept on Hand
Even parts with a long service life are not completely free from possible failure. It is recommend-
ed that users have on hand spare parts for those parts which, if they become defective, will make
it impossible to continue measurement.
[Membrane Assembly Locknut (part number: K9171CH)]
It is recommended that users have spare parts for the locknut on hand in preparation for possible
failure.
[Spare Sensor Assembly]
If the sensor assembly remains unused over a prolonged period, the electrolyte may change in
quality or some anomalies may occur in the permeable membrane. Consequently, these ma-
terials must be replaced with new ones before you can use the sensor. Although it is desirable
that users always try to avoid storing the sensor assembly for long periods, the manufacturer
recommends that users keep a spare part on hand for the sensor assembly in anticipation of an
unexpected failure. Do not store the sensor with the electrolyte removed. Otherwise, any residual
electrolyte may become concentrated, harming the lead electrode or other mechanisms. If the
sensor must be stored with the electrolyte removed, completely clean the inside of the sensor
with clean water (repeat injecting and draining the water several times) before it is stored.
Note: If the sensor is stored without the electrolyte, repeat injecting and draining the electrolyte several times before you reuse it.
4th Edition : Apr 05,2011
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