Xylem WTW SenTix H User manual

OPERATING MANUAL
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SenTix®
PH ELECTRODES WITH LIQUID REFERENCE SYSTEM AND GROUND JUNCTION
SenTix®H
SenTix®HW
SenTix®HWD
OPERATING MANUAL

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SenTix®
2
Copyright © 2016, Xylem Analytics Germany GmbH
Printed in Germany.

SenTix®Technical data
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Technical data
General data
Measurement and application characteristics
Shaft dimensions, shaft material, electrical connection
* Connection cable not included in the scope of delivery of the electrode (see
WEAR PARTS AND ACCESSORIES)
** Coaxial plug according to DIN 19262
Model Reference electro-
lyte
Junction NTC Special features
SenTix®H KCl 3 mol/L, Ag+free Ground No Adjustable ground junc-
tion
SenTix®HW KCl 3 mol/L, Ag+free Ground No Adjustable ground junc-
tion
SenTix®HWD KCl 3 mol/L, Ag+free Ground Yes
Model pH measur-
ing range
Allowed tempera-
ture range
Membrane resis-
tance at 25 °C
Typical application
SenTix®H 0 ... 14 0 ... 80 °C < 2 GOhm Highly alkaline and
highly saltine solutions
SenTix®HW 0 ... 14 0 ... 60 °C < 800 MOhm Solutions with low ion
contents, emulsions,
suspensions
SenTix®HWD 0 ... 14 -5 ... 100 °C < 600 MOhm
Model Shaft Electrical connection
Length
[mm]
Ø[mm] Material Electrode
connection
Meter connection Cable
length
SenTix®H 170 12 Glass S7 plug-in
connector
depending on S7 cable*
SenTix®HW 170 12 Glass S7 plug-in
connector
depending on S7 cable*
SenTix®HWD 170 12 Glass Fixed cable DIN** + banana 1 m

Technical data SenTix®
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Commissioning, measuring, calibration
Commissioning The electrode is filled with reference electrolyte solution in the factory. Pre-
pare the electrode for measuring as follows:
Open the refilling opening for the reference electrolyte solution. Depend-
ing on the model, the stopper of the refilling opening is an elastomer stop-
per or a slider.
The refilling opening must always be open during calibration and
measurement!
Remove the watering cap from the electrode tip. Possible salt deposits in
the area of the watering cap do not affect the measuring characteristics
and can easily be removed with deionized water.
Connect the electrode to the meter
Calibrate the electrode according to the operating manual of the meter.
When doing so, observe the general rules on the following page.
Ground junction of
the SenTix HWD
When the SenTix HWD electrode is delivered, the ground sleeve is fixed with
a shrinkable tubing. For commissioning, carefully remove the shrinkable
tubing with a sharp knife or scalpel.
Caution:
The ground sleeve is made of synthetic material and can easily be
damaged!
To moisten the ground surfaces hold the electrode in a vertical position with
the refill opening open and carefully loosen the ground junction by turning it
slightly until reference electrolyte solution comes out of the junction. Then put
the ground sleeve on again while turning it slightly.
Please keep the watering cap. It is required for the electrode to
be stored. Always keep the watering cap clean.
Refilling
opening
Refilling
opening
2
1

SenTix®Technical data
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Ground junction of
SenTix H and
SenTix HW
With the ground junction of the SenTix H and SenTix HW electrodes, the
electrode outflow can be adjusted with a thread:
Hold the electrode with the pH glass membrane pointing downward. Using
the provided special wrench, open the ground junction until some electro-
lyte solution can be seen to come out of the junction and all ground sur-
faces are completely moist.
Carefully and using little power close the junction until the contact between
the rough ground surfaces can be noticed as a resistance. The electrode
is now ready to measure.
Caution: Always use very little power to close the junction so the
ground surfaces are not damaged!
The ground junction can be opened further so that more electrolyte solu-
tion comes out.
Calibration
and measurement:
General rules
Make sure the refilling opening for the reference electrolyte solution is
open.
Avoid the displacement of any solution (sample or buffer solution) from
one measurement to the next by taking the following measures:
– Shortly rinse the calibration and sample beakers with the solution the
beakers are to be filled with next.
– Between measurements, rinse the electrode with the solution that fol-
lows. Alternatively, you can also rinse the electrode with deionized wa-
ter and then carefully dab it dry.
Immerse the electrode in the solution in a vertical or slightly tilted position.
Make sure the immersion depth is correct. The ground junction must be
completely submersed in the solution. At the same time, the level of the
reference electrolyte must be at least 2 cm above the level of the solution.
Provide approximately the same stirring conditions for measuring as for
calibrating.
Special wrench
Groundjunction
OpenClose

Storage SenTix®
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Subsequent cali-
brations
The frequency of subsequent calibrations depends on the application. Many
meters provide an option where you can enter a calibration interval. After the
calibration interval has expired, the meter will automatically remind you of the
due calibration.
Storage
During short
measuring breaks
With the refilling opening open, immerse the electrode in reference
electrolyte (KCl 3 mol/L, Ag+free). Observe the minimum depth of
immersion. Prior to the next measurement, shortly rinse the electrode with
the test sample or deionized water.
Overnight or
longer
Put the clean electrode in the watering cap that is filled with reference
electrolyte (KCl 3 mol/L, Ag+free) and close the refilling opening.
NOTE
pH electrodes must not be stored dry or in deionized water. The elec-
trode could be permanently damaged by this. If the liquid in the
watering cap has dried up, condition the electrode in reference electro-
lyte (KCl 3 mol/L, Ag+ + free) for at least 24 hours.
Aging
Please note that pH electrodes are consumables. Every pH electrode under-
goes a natural aging process. With aging, the responding behavior becomes
slower and slower and the electrode slope and asymmetry change. More-
over, extreme operating conditions can considerably shorten the lifetime of
the electrode. These are:
Strong acids or lyes, hydrofluoric acid, organic solvents, oils, fats, bro-
mides, sulfides, iodides, proteins
High temperatures
High changes in pH and temperature.
The warranty does not cover failure caused by measuring conditions and
mechanical damage.
Prevent contact of the pH membrane to the beaker bottom to
avoid scratches on the pH membrane.
During longer storing periods, salt sediments may develop on the
watering cap. They do not affect the measuring characteristics
and can easily be removed with deionized water when the elec-
trode is put into operation again.

SenTix®Maintenance and cleaning
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Maintenance and cleaning
Refilling the
reference
electrolyte
During operation, a small amount of reference electrolyte leaks through the
junction from the electrode into the test sample. If the level of reference elec-
trolyte becomes too low with time, refill it through the refilling opening. Refill-
ing is very easy with the enclosed dropping bottle. Proceed as follows:
Cut off the tip of the dropping bottle at a right angle until the opening in the
tip can be seen
Open the refilling opening of the electrode
Press the tip of the dropping bottle into the refilling opening while turning
it slightly
Pump the reference electrolyte in the shaft using the dropping bottle
Pull the dropping bottle out of the refilling opening while turning it slightly
if necessary.
Cleaning Remove water-soluble contamination by rinsing with deionized water. Re-
move other contamination as follows:
Contamination Cleaning procedure
Fat and oil Rinse with water containing household
washing-up liquid
Lime and hydroxide deposits Rinse with citric acid (10 % by weight)
Proteins Immerse in pepsin cleaning solution PEP/pH
for approx. 1 hour.
Note: Make sure the level of the reference
electrolyte is above that of the cleaning solu-
tion.
Hydrofluoric acid, hot phosphoric acid and strong alkaline solu-
tions destroy the glass membrane.

Wear parts and accessories SenTix®
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If you want to clean and rinse the ground junction, you can open it as follows:
SenTix H and SenTix HW: completely unscrew the ground stopper (see
figure on Seite 5).
SenTix HWD: slide the ground sleeve from the ground stopper towards the
shaft while turning it slightly.
After cleaning Rinse the electrode with deionized water and condition it in reference
electrolyte solution for at least 1 hour. Then recalibrate the electrode.
Wear parts and accessories
Disposal
At the end of its operational lifetime, the electrode must be returned to the
disposal or return system statutory in your country (electronic waste). If you
have any questions, please contact your supplier.
Description Model Order no.
Reference electrolyte solution 250 mL
(KCl 3 mol/L, Ag+free)
KCl-250 109 705
Pepsin cleaning solution 3 x 250 ml PEP/pH 109 648
Connection cable S7 plug-in connector/DIN, 1 m AS/DIN 108 110
Connection cable S7 plug-in connector/DIN, 3 m AS/DIN-3 108 112
Connection cable S7 plug-in connector/BNC,
1m
AS/BNC 108 114
Plastic arming for SenTix®pH electrodes A pHLab/K 903 841

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Am Achalaich 11
82362 Weilheim
Germany
Xylem Analytics Germany
Sales GmbH & Co. KG
WTW
Am Achalaich 11
82362 Weilheim
Germany
Tel.:
Fax:
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