wtw SensoLyt MPP-A Pt Series User manual

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SensoLyt®MPP-A Pt
ORP combination electrode
Operating manual

Fields of application SensoLyt®MPP-A Pt
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1 Fields of application
Measurements in normally charged surface water and waste water.
2 Identification of the electrode
A series number is impressed on the ORP electrode. Have this number ready
in case of queries to the WTW service department.
The series number provides the following information:
Series number The number is impressed on the armoring.
3 Commissioning
Commissioning Prepare the combination electrode for measuring as follows:
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.
Install the electrode in the armature (see operating manual of the arma-
ture). Before installing the electrode, slightly lubricate the O ring of the
armature (black area) with the grease provided.
If necessary, carry out an activation first (see MAINTENANCE (REGENERA-
TION), page 12)
Note
Please keep the watering cap. It is required to store the combination
electrode. Always keep the watering cap clean.
1Test department
2Manufacturing year 20... (example: 2010)
3Calendar week of manufacturing (CW 03)
4Lot number (99)
5Production number (123)
A100399123
21345

SensoLyt®MPP-A Pt Calibrating, measuring
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4 Calibrating, measuring
Note
See operating manual of the meter.
Note
Take off the watering cap when you want to calibrate or measure.
Conversion to
standard hydrogen
electrode
UH= UMeas + URef
URef depends on the reference system and temperature and is given in the
following table (see also DIN 38404-6 for the system, Ag/AgCl/
saturated KCl):
with: UH= ORP, referring to the standard hydrogen electrode
UMeas = Measured ORP
URef = Voltage of the reference system compared to the standard
hydrogen electrode
T (°C) URef [mV] T (°C) URef [mV]
SensoLyt®MPP-A Pt SensoLyt®MPP-A Pt
0 +221 35 +187
5 +216 40 +181
10 +212 45 +176
15 +207 50 +171
20 +202 55 +165
25 +197 60 +160
30 +192

Maintenance (regeneration) SensoLyt®MPP-A Pt
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5 Maintenance (regeneration)
First-time
activation during
installation and as
required
For first-time activation, use the activating powder provided with the SORT/
RH reagent set. Use a paper towel to gather a small amount of activating
powder. Using moderate pressure, press the activating powder against the
moist (but not dripping) platinum electrode from two opposite sides and turn
the electrode to and fro several times. Activation happens mainly due to
abrasion. Then remove the adherent remains of activating powder under
running water with a soft brush (e.g. toothbrush).
Activation during
very long set-up
times
When changing from oxidizing to reducing test solutions and vice versa this
can result in set-up times that can take significantly more than an hour. In this
case pretreatment (activation) of the platinum surface can shorten the set-up
time. The type of pretreatment (reducing or oxidizing) is based on the pH val-
ue and the ORP voltage (UH) of the test solution where the latter must be es-
timated for the first measurement.
The type of pretreatment can then be determined using the following diagram
where UHrefers to the normal hydrogen electrode:
Oxidizing pretreat-
ment
Immerse the platinum electrode for two to three
days in a sulfuric clorina solution. Clorina powder
for producing the solution is included in the SORT/
RH reagent set.
Note: The junction must not be immersed in the clo-
rina solution (see figure below)!
Reducing pretreat-
ment
When the electrode is ready for the test immerse it
in the RH 28 ORP buffer solution and wait for a sta-
ble measured value.
1000
800
600
400
200
20 4810 12 146
0
pH value
UHin mV oxidizing pretreatment
reducing pretreatment

SensoLyt®MPP-A Pt Storage
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Note
The platinum electrode (1) should be completely covered during the pretreat-
ment but the electrode must not be immersed in the solution up to the refer-
ence system with the hole junction (2) (see following figure).
Note
Detailed information on activating platinum electrodes, such as how to pro-
duce the clorina solution, is given in the WTW application report entitled RE-
GENERATING ORP ELECTRODES. The application report is included in the
SORT/RH reagent set.
6Storage
During short
measuring breaks
Immerse the combination electrode in reference electrolyte (KCl 3 mol/L, Ag+
free). Prior to the next measurement, shortly rinse the combination electrode
with the test sample or deionized water.
Overnight or
longer
Put the clean combination electrode in the watering cap that is filled with
reference electrolyte (KCl 3 mol/L, Ag+free).
Note
The combination electrode must not be stored dry or in deionized water. The
combination electrode could be permanently damaged by this.
Note
During longer storing periods, salt sediments may develop on the watering
cap. They do not affect the measuring characteristics and can easily be re-
moved with deionized water when the combination electrode is put into oper-
ation again.
Maximum depth of immersion

Cleaning SensoLyt®MPP-A Pt
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7 Cleaning
Cleaning
procedure
8 Accessories
Contamination Cleaning
Gross contamination at the junction Carefully brush off contamination
under running water using a soft
toothbrush
Fat, oil, protein-containing coatings
and similar substances
Remove with household washing-
up liquid
Description Model Order no.
Reference electrolyte solution 3 mol/l KCl,
Ag+free (250 ml)
KCl-250 109 705
Reagent set for regenerating ORP platinum
electrodes, consisting of 10 g activation
powder and 30 g clorina powder
SORT/RH 109 730
ORP buffer solution for checking ORP
electrodes UH= 427 mV (250 ml)
RH 28 109 740

SensoLyt®MPP-A Pt Technical data
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9 Technical data
* The electrode meets the requirements according to article 3(3) of the
directive, 97/23/EC ("pressure equipment directive").
General features ORP electrode Platinum ring
Reference electrolyte Polymer electrolyte
Shunt conduction element Ag/AgCl
Junction 2-hole junction
Temperature sensor Integrated NTC 30
(30 kat 25 °C / 77 °F)
Measurement and
application
characteristics
ORP application range -2000 ... +2000 mV
Allowed temperature range 0 ... 50 °C (32 ... 122 °F)
Minimum immersion depth 25 mm
Precision of temperature
sensor
± 0.2 K
Response time t99 < 130 s
Allowed pH range of the
measuring medium
4 ... 12
Pressure resistance * IP 68 (106Pa or 10 bar)
Materials Shaft Glass
Armoring POM
Watering cap PE
S7 protection cap PBTP
Electrical
connection
Plug-in system (S7)
Storage With watering cap, filled with KCl 3 mol/L, Ag+free
Disposal Residual waste

Wissenschaftlich-Technische Werkstätten GmbH
Dr.-Karl-Slevogt-Straße 1
D-82362 Weilheim
Germany
Tel: [phone]
[phone]
Fax: [phone]
E-Mail: [e-mail]
Internet: http://www.WTW.com