wtw SensoLyt MPP-A Pt Series Operating instructions

Brand: wtw

Model: SensoLyt MPP-A Pt Series

Type: Operating instructions

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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 M

AINTENANCE (REGENERA-

TION), page 12)

Note

Please keep the watering cap. It is required to store the combination

electrode. Always keep the watering cap clean.

1 Test department

2 Manufacturing year 20... (example: 2010)

3 Calendar week of manufacturing (CW 03)

4 Lot number (99)

5 Production 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

= U

Meas

+ U

Ref

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: U

= ORP, referring to the standard hydrogen electrode

Meas

= Measured ORP

Ref

= Voltage of the reference system compared to the standard

hydrogen electrode

T (°C) U

Ref

[mV] T (°C) U

Ref

[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 (U

) 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 U

refers 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

pH value

in 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 R

E-

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,

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 U

= 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 t

< 130 s

Allowed pH range of the

measuring medium

4 ... 12

Pressure resistance * IP 68 (10

Pa 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: +49 (0) 881 183-0

+49 (0) 881 183-100

Fax: +49 (0) 881 183-420

E-Mail: Info@WTW.com

Internet: http://www.WTW.com

wtw SensoLyt MPP-A Pt Series Operating instructions

wtw SensoLyt MPP-A Pt Series Operating instructions

wtw SensoLyt MPP-A Pt Series Operating instructions

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