wtw Stirrox G User manual

OPERATING MANUAL
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StirrOx G
DISSOLVED OXYGEN SENSOR WITH INTEGRATED STIRRER
OPERATING MANUAL

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StirrOx G
Copyright © 2018 Xylem Analytics Germany GmbH
Printed in Germany.

StirrOx G Contents
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StirrOx G - Contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 Measuring / Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Measuring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Maintenance, cleaning, replacement. . . . . . . . . . . . . . . . . . . 8
5.1 General maintenance instructions . . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Outside cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.3 Changing the electrolyte and membrane cap . . . . . . . . . . . . . . 9
5.4 Cleaning the electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.5 Checking the sensor for freedom from zero-current . . . . . . . . 14
5.6 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6 What to do if .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8 Wear parts and accessories. . . . . . . . . . . . . . . . . . . . . . . . . 19

Contents StirrOx G
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StirrOx G Overview
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1 Overview
Structure
Recommended
application range
BOD measurements in BOD sample bottles.
1Shaft housing
2Connection head
3On/Off key for stirrer
4Cable screw joint
5Stirring paddle
6WP-ST membrane cap (filled with electrolyte solution)
7Gold working electrode (cathode)
8Insulator
9Lead counter electrode (anode)
10 Ventilation area
11 Temperature sensor and auxiliary electrode
1
3
4
5
7
8
9
11
10
6
2

Safety instructions StirrOx G
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2 Safety instructions
This operating manual contains special instructions that must be followed
during the operation of the D.O. sensor.
Always keep this operating manual in the vicinity of the sensor.
Special user
qualifications
The membrane cap of the D.O. sensor is filled with a small amount of an
alkaline electrolyte solution. All maintenance work that requires dealing with
the electrolyte solution must only be carried out by persons who know how to
safely deal with chemicals.
General safety
instructions
The individual chapters of this operating manual use safety labels like the one
below to indicate danger:
CAUTION
indicates instructions that must be followed precisely in order to avoid
slight injuries or damage to the instrument or the environment.
3 Commissioning
Scope of delivery D.O. sensor StirrOx G, filled with electrolyte solution and ready to operate
Calibration and storage vessel, OxiCal®-ST
ZBK-ST accessory kit, comprising:
– 3 exchange membrane caps, WP-ST
– Electrolyte solution, ELY/G
– Cleaning solution, RL/G
– Polishing strip, SF 300
Operating manual
Getting the sensor
ready for
measuring
Connect the 8-pin plug to the Oxi input and the 2-pin plug to the stirrer
connection of the meter (see operating manual of the meter). The sensor is
immediately ready to measure. It is not necessary to polarize the sensor.
The membrane cap that is mounted on the sensor for delivery
serves mainly as a transport protection. Depending on the duration
of the transport and storage period, it may have a shortened oper-
ational lifetime. If the measuring system cannot be calibrated (error
message of the instrument), please proceed according to section
REPLACING THE ELECTROLYTE SOLUTION AND MEMBRANE CAP.

StirrOx G Measuring / Operation
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4 Measuring / Operation
4.1 Calibration
4.2 Measuring
Depth of
immersion
Observe the minimum and maximum depth of immersion of the sensor. The
temperature sensor / auxiliary electrode must be completely submersed for
measurement.
CAUTION
The sensor is designed for immersion measurements in BOD bottles.
Do not expose the sensor to overpressure (see chapter 7 TECHNICAL
DATA), e.g. due to sealed installation in a pressurized vessel. Danger of
damage to the sensor.
Use of the
integrated
stirrer
The sensor is equipped with an integrated stirring system for the incident flow
of the membrane.
Pressing the On/Off key switches the stirrer on. Pressing once more switches
the stirrer off again.
Measurement in
sample bottles
The displacement volume of the StirrOx G (5,6 ml) is dimensioned so that the
sample bottle is closed free of air bubbles after inserting the sealing plug. If
you use bottles other than the Karlsruhe bottles available at WTW (see
chapter 8 WEAR PARTS AND ACCESSORIES), use WHEATON bottles or bottles
with NS 19 standard ground joint only. The plug should have a displacement
volume of 5.6 to 8.6 ml.
For calibration, please refer to the operating manual of the mea-
suring instrument.
Min. approx. 49 mm
Max. 83 mm
Depth of immersion

Maintenance, cleaning, replacement StirrOx G
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4.3 Storage
Always store the sensor in the calibration and storage vessel at a
temperature in the range 0 ... +50 °C (32 ... 122 °F). Make sure that the
sponge in the calibration and storage vessel is always moist.
Calibration and
storage vessel,
OxiCal®-ST
Moisten the sponge:
Screw out the insert (1).
Take out the sponge (2), wet it, then slightly squeeze it out.
Put in the sponge and screw the insert in the calibration and storage
vessel again.
Sta-ST stand The Sta-ST stand (see chapter 8 WEAR PARTS AND ACCESSORIES) enables
you to place the calibration and storage vessel with the sensor in an upright,
tilt resistant position on a table.
5 Maintenance, cleaning, replacement
5.1 General maintenance instructions
For your safety Note the following safety instructions when handling electrolyte and cleaning
solutions:
CAUTION
The ELY/G electrolyte solution and RL-G cleaning solution irritate the
eyes and skin. Note the following points when dealing with these
solutions:
During working activities, always wear suitable protective gloves
and protective goggles/face shield.
If the solutions come into contact with the skin, rinse thoroughly with
water and immediately change contaminated clothing.
After each measurement series (before storing the sensor) clean
the sensor (exterior cleaning).

StirrOx G Maintenance, cleaning, replacement
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If the solutions come into contact with the eyes, rinse thoroughly
with water and consult a doctor.
Follow the safety datasheet.
CAUTION
Before all maintenance activities, disconnect the sensor from the
instrument.
Removable stirring
paddle
The stirring paddle can be pulled off for maintenance purposes. After
finishing the maintenance activities reinsert the stirring paddle into the
receptacle as far as it will go. Then turn the stirring paddle so that the paddle
face is positioned in center under the membrane cap.
5.2 Outside cleaning
Cleaning agents
After cleaning, thoroughly rinse with deionized water and recalibrate if
necessary.
5.3 Changing the electrolyte and membrane cap
CAUTION
Before starting to work with the sensor, please note the GENERAL
MAINTENANCE INSTRUCTIONS on page 8.
General
information
WTW delivers the sensor ready to operate (see section 3). The electrolyte
solution and membrane cap must only be replaced if:
a calibration error occurs and the membrane is heavily contaminated
the membrane is damaged
the electrolyte solution is exhausted.
in case of a leak message by the measuring instrument
Information on how to order wear parts and maintenance equip-
ment can be found in chapter 8 WEAR PARTS AND ACCESSORIES.
Contamination Cleaning procedure
Lime sediments Immerse in acetic acid for 1 minute (volume
share = 10 %)
Fat/oil Clean with warm water that contains
washing-up liquid

Maintenance, cleaning, replacement StirrOx G
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Changing the electrolyte and membrane cap
Pull off the stirring paddle and
screw off the membrane
head.
Caution: Electrolyte solution!
For disposal of the membrane
head and electrolyte solution,
see section 5.6.
Rinse the sensor head with
deionized water.
Carefully rub and dry the
counter electrode with a lint-
free paper towel.
Immerse the sensor head
including the counter
electrode in RL/G cleaning
solution.
Allow to react for 1 to 3
minutes.
Thoroughly rinse the sensor
head with deionized water.
Water the counter electrode in
deionized water for at least
10 minutes.
RL/G
H O
2