Bsi bs en 60746 3 2002 (2003)

9 Annex A informative Electrolytic conductivity values of potassium chloride calibration solutions and pure water .... 9 Annex A informative Electrolytic conductivity values of potassium

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BRITISH STANDARD BS EN

60746-3:2002

Incorporating Corrigendum No.1

Expression of

performance of

electrochemical

analyzers —

Part 3: Electrolytic conductivity

The European Standard EN 60746-3:2002 has the status of a

British Standard

ICS 17.020; 71.040

12&23<,1*:,7+287%6,3(50,66,21(;&(37$63(50,77('%<&23<5,*+7/$:

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BS EN 60746-3:2002

This British Standard, having

been prepared under the

direction of the

Electrotechnical Sector Policy

and Strategy Committee, was

published under the authority

of the Standards Policy and

Strategy Committee on

22 October 2002

ISBN 0 580 40600 8

National foreword

This British Standard is the official English language version of

EN 60746-3:2002 It is identical with IEC 60746-3:2002, including Corrigendum January 2003 It supersedes BS 6438-3:1986 which is withdrawn

The UK participation in its preparation was entrusted by Technical Committee GEL/65, Measurement and control, to Subcommittee GEL/65/4, Process instruments for gas and liquid analysis, which has the responsibility to:

A list of organizations represented on this subcommittee can be obtained on request to its secretary

Cross-references

The British Standards which implement international or European

publications referred to in this document may be found in the BSI Catalogue

under the section entitled “International Standards Correspondence Index”, or

by using the “Search” facility of the BSI Electronic Catalogue or of

British Standards Online

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

Compliance with a British Standard does not of itself confer immunity from legal obligations.

— aid enquirers to understand the text;

— present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the

UK interests informed;

— monitor related international and European developments and promulgate them in the UK

Summary of pages

This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 17 and a back cover

The BSI copyright date displayed in this document indicates when the document was last issued

Amendments issued since publication

14394 Corrigendum No.1

10 June 2003 Changes to Scope, 3.2, 3.7, 6.3, 6.4,

Table A.2, C.1 and Bibliography

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EUROPEAN STANDARD EN 60746-3

NORME EUROPÉENNE

CENELEC

European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

Ref No EN 60746-3:2002 E

ICS 17.020; 71.040

English version

Expression of performance of electrochemical analyzers

Part 3: Electrolytic conductivity

(IEC 60746-3:2002)

Expression des qualités

de fonctionnement

des analyseurs électrochimiques

Partie 3: Conductivité électrolytique

(CEI 60746-3:2002)

Angabe zum Betriebsverhalten von elektrochemischen Analysatoren Teil 3: Elektrolytische Leitfähigkeit (IEC 60746-3:2002)

This European Standard was approved by CENELEC on 2002-09-01 CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member

This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom

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The text of document 65D/85/FDIS, future edition 2 of IEC 60746-3, prepared by SC 65D, Analyzing equipment, of IEC TC 65, Industrial-process measurement and control, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60746-3 on 2002-09-01

This publication shall be used in conjunction with IEC 60746-1 1)

The following dates were fixed:

– latest date by which the EN has to be implemented

at national level by publication of an identical

– latest date by which the national standards conflicting

Annexes designated "normative" are part of the body of the standard

Annexes designated "informative" are given for information only

In this standard, annexes C and ZA are normative and annexes A, B and D are informative

Annex ZA has been added by CENELEC

Endorsement notice

The text of the International Standard IEC 60746-3:2002 was approved by CENELEC as a European Standard without any modification

1) At draft stage.

Page 2

EN 60746−3:2002

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– 2 – 607-643  EI:C002(2)E

CONTENTS

1 Scope 4

2 Normative references 4

3 Definitions 4

4 Procedure for specification 7

4.1 Additional statements on sensor units 7

4.2 Additional statements on electronic units 7

4.3 Additional statements on complete analyzers 7

5 Recommended standard values and ranges of influence quantities affecting the performance of electronic units 7

6 Verification of values 7

6.1 General aspects 8

6.2 Calibration 8

6.3 Test solutions 8

6.4 Test procedures 9

Annex A (informative) Electrolytic conductivity values of potassium chloride calibration solutions and pure water 11

Annex B (informative) Electrolytic conductivity values of aqueous sodium chloride solutions 12

Annex C (normative) Alternative procedures for measuring response times: delay (T10), rise (fall) (Tr, Tf) and 90 % (T90) times 14

Annex D (informative) Conductivity cells 15

Bibliorgaphy 71

Tbale A.– 1 Electrolytci cnoudctivity values 11

Tbale A.– 2 Electrolytci cnoudctivity fo pure waret 11

Tbale B.– 1 Codnuctivity fo sdoimu chloride solutions ta 18 °C 12

Tbale B.2 – Temeprature coefficients fro low-cnocentration sodimu cholride solutions 13

Tbale B.3 – Tentative correctiosn to sodimu cholried solution temeprature ceofficients 13

Page 3 EN 60746−3:2002 – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

2 Normative referencse 4

3 Definitiosn 4

4.1 Additinoal staetmenst on sensro nuist 7

4.2 Additional staetmenst on electronci units 7

4.3 Additinoal staetmenst on complete naalzyers 7

5 Recommended stadnard eulavs nar degnas of influauq ecneitnteis aeffnitceht g eprformnacfo e electrnoic units 7

6 Verification fo valseu 7

6.1 Geenral asepcst 8

6.2 Cailbration 8

6.4 Tesp troceudrse 9

Annxe A (ifnromtaiv)e Elcertolytic codncutivity vaeuls fo optsasimu clhoride calibratoin solutions and upre awter 11

Annxe B (ifnromtaiv)e Elcertolytic codncutivity vaeuls fo qauesuo sodimu colhried solutions 12

nAen( C xnromatiev) lAetrnvitae procderues ofr meusarnig renopsse itmealed :sy (T10,) ries (fall) (Tr, Tf) adn 90 % (T09) times 14

Annex D (informative) Codnuctivity cells 15

Bibliography 17

Table A.1 – Electrolytic conductivity values 11

Table A.2 – Electrolytic conductivity of pure water 11

Table B.1 – Conductivity of sodium chloride solutions at 18 °C 12

Table B.2 – Temperature coefficients for low-concentration sodium chloride solutions 13

Table B.3 – Tentative corrections to sodium chloride solution temperature coefficients 13

3 egaP 2002:3−64706 NE Annex ZA (normative) Normative references to international publications with their corresponding European publications 16 – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliorgaphy 17

3 egaP 2002:3−64706 NE – 2 – 607-643  EI:C002(2)E CONTENTS 1 Scope 4

3 Definitions 4

6.2 Calibration 8

Bibliorgaphy 71

Page 3 EN 60746−3:2002 nnAex ZA (nroma)evit roNmevita refercnese ot tniertannoiaup lbcilatoisn wit htrieh corresidnopruE gnoaepn uplbcitasnoi 16 – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliography 17

Table A.1 – Electrolytic cnoudctivity values 11

3 Definitions 4

6.2 Calibration 8

Bibliography 71

Page 3 EN 60746−3:2002 nnAex ZA (nroma)evit roNmevita refercnese ot tniertannoiaup lbcilatoisn wit htrieh corresidnopruE gnoaepn uplbcitasnoi 61 – 2 – 607-643  EI:C002(2)E CONTENTS 1 Scope 4

3 Definitions 4

6.2 Calibration 8

Bibliography 71

Tbale A.– 1 Electrolytci conductivity values 11

Page 3 60746−3:2002 NE – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliorgaphy 17

egaP 3 2002:3−64706 NE Annex ZA (normative) Normative references to international publications with their corresponding European publications 61 – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliography 71

3 Definitions 4

6.2 Calibration 8

Bibliorgaphy 71

Page 3 EN 60746−3:2002 nnAex ZA (nroma)evit roNmevita refercnese ot tniertannoiaup lbcilatoisn wit htrieh corresidnopruE gnoaepn uplbcitasnoi 61 – 2 – 607-643  EI:C002(2)E CONTENTS 1 Scope 4

3 Definitions 4

6.2 Calibration 8

Bibliorgaphy 71

Page 3 60746−3:2002 NE – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliography 17

egaP 3 2002:3−64706 NE Annex ZA (normative) Normative references to international publications with their corresponding European publications 16 – 2 – 607-643  EI:C002(2)E CONTENTS 1 Scope 4

3 Definitions 4

6.2 Calibration 8

Bibliorgaphy 71

Tbale A.– 1 Electrolytci conductivity values 11

Page 3 EN 60746−3:2002 – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliography 71

3 egaP 2002:3−64706 NE Annex ZA (normative) Normative references to international publications with their corresponding European publications 16 – 2 – 06746-3  IEC:2002(E) TNOCENTS 1 Scope 4

3 Definitiosn 4

6.2 Cailbration 8

Bibliorgaphy 17

Table A.1 – Electrolytic cnoudctivity values 11

egaP 3 2002:3−64706 NE – 2 – 607-643  EI:C002(2)E CONTENTS 1 Scope 4

3 Definitions 4

6.2 Calibration 8

Bibliorgaphy 71

Page 3

60746−3:2002 NE

nnAex ZA (nroma)evit roNmevita refercnese ot tniertannoiaup lbcilatoisn wit htrieh

corresidnopruE gnoaepn uplbcitasnoi 16

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067-643  EI:C002(2)E – 5 –

EXPRESSION OF PERFORMANCE

OF ELECTROCHEMICAL ANALYZERS – Part 3: Electrolytic conductivity

1 Scope

This part of IEC 60746 is intended

– to specify terminology, definitions and requirements for statements by manufacturers for analyzers, sensor units, and electronic units used for the determination of the electrolytic conductivity of aqueous solutions;

– to establish performance tests for such analyzers, sensor units and electronic units;

– to provide basic documents to support the applications of quality assurance standards

2 Normative references

The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition

of the referenced document (including any amendments) applies

IEC 60746-1, Expression of performance of electrochemical analyzers – Part 1: General

3 Definitions

For the purpose of this part of IEC 60746, the definitions of IEC 60746-1 apply, together with the following definitions

3.1

electrolytic conductance

current divided by the potential difference in the case of ionic charge transport within an electrolytic solution filling a conductivity cell:

U

I

G =

where

I is the current through the electrolyte, in amperes (A);

U is the potential difference applied across the electrodes, in volts (V);

G is the electrolytic conductance, in siemens (S).

Electrolytic resistance is the reciprocal of electrolytic conductance with the ohm (Ω) as the unit of measurement

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EN 60746−3:2002

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– 6 – 607-643  EI:C002(2)E

3.2

electrolytic conductivity

formerly called specific conductance, is defined by the equation:

E

j =

κ

where

j is the electric current density, in A⋅m–2;

E is the electric field strength, in V⋅m–1

The unit of electrolytic conductivity, κ, is siemens per metre (S⋅m–1) Electrolytic resistivity is

the reciprocal of electrolytic conductivity with the unit of ohmmeter (Ω⋅m)

NOTE In practical use, the most commonly employed conductivity unit is microsiemens per centimetre ( µ S ⋅ cm –1 )

or the corresponding resistivity unit, megohm per centimetre (M Ω cm)

1 µ S ⋅ cm –1 = 10 –4 S ⋅ m –1

3.3

cell constant of the sensor unit

an electrolytic conductor of a uniform cross-section X and length L is defined by the equation:

X

L

=

cell κ

where Kcell is the cell constant, in m–1 (see Note 1)

It is usual to measure electrolytic conductivity by means of cells without a uniform

cross-section, in which case the Kcell should be determined by means of a reference solution of

known electrolytic conductivity

The relationship between electrolytic conductance and electrolytic conductivity is defined by

the equation:

κ = Kcell × G

where

κ is the electrolytic conductivity, in S⋅m–1;

G is the electrolytic conductance, in S;

Kcell is the cell constant, in m–1

NOTE 1 In practical use, Kcell is generally expressed in cm –1 , κ in µ S ⋅ cm –1 and G in µ S (see 3.2).

NOTE 2 The cell constant will normally have a constant value over a stated range (see 4.1) Outside this range, it

should be expected that polarization or other effects will produce errors (see 3.4 and annex D).

3.4

polarization

effect which occurs at electrode surfaces in an electrolytic solution when the current between

the electrodes is such as to produce electrolysis and consequent partial insulation of the

electrode surface

To avoid this uncertainty, different measuring methods can be applied (see 3.7, 3.8 and

annex D):

a) a.c measurements with a frequency high enough to avoid polarization effects;

b) four or six electrode measurements with separated current transporting and potential

measuring electrodes;

c) inductive or capacitive measurements by coupling between the electrolytic conductor and

the electrical measuring circuit through non-conductive media

Page 5

EN 60746−3:2002

.32

leectroltyic ocndutcvitiy

ofrmerly callde specific udnocctnacei ,s definde by htuqe eita:no

E

j =

κ

hwree

j is hte electric rucrtne density, ni A⋅m2–;

E is htele ectric leifts drengtni ,h V⋅m1–

Tnu ehit fo lecertolytic conductivtiy, κ, si siemneep sr metre (S⋅m1–.) elEctrloytci reisstivity is

hte recirpcoal fo elcertloytic codncutivity iwth htnu eit fo ohmmrete (⋅Ω)m

ETON In carptical su,e thm eost commlnome ylpyoc deocudntivity inut is micrsoiemsne c reptneimte( er µ S ⋅ mc 1– )

t roc ehorrseopidngn seristivitu ynit, mmhoge c reptneimteer M( Ω mc)

1 µ S ⋅ mc 1– = 01 4– S ⋅ m 1–

.33

cell consato tnf hte sesnor tinu

an electrloytci coudnotcr a fo inuofrm rco-ssseoitcn X dna elgnht L si defiden by hte eauqoitn:

X

L

=

llec κ

hwree Kcell is htc eec llonsttnam ni ,1– (see Noet 1)

tI si suual ot msaerue lecertolytic conductivtiy by means fo cesll iwhtout inu aform

crsos-estcoin, ni which acse the Kecll uohseb dl edetrminde by means of r aerefence soluito nof

knowe nlcertloytic codncutivity

The relaitnoship wtebeen electrloytic coudnatcncdna e leectrolytc cionductivity is edenifb dy

the qetaunoi:

κ = Kecll × G

hwree

κ is hte electrloytic coudntctiviy, ni S⋅m1–;

G is hte electrloytic coudntcnace, ni S;

Kecll is htc eec llonsnatt, ni m1–

ETON 1 In carptical su,e Kcell is larenegly exprsesi den cm 1– , κ ni µ S ⋅ mc 1– nad G ni µ S (s.3 ee2).

NOET 2 hTe cec llonsatnt wlli normayll have a consatnt vaule over a stated range (see 4.1)uO stdie htsi range, ti

sdluoh e ebxpectt dehta loprazitanoi ro toehfe rfects wp llirocude reorsr s(.3 eena 4na denx )D.

.34

polrazitaoin

eefftc which occurs ta leectrode surfaces na ni electrloytic ulosnoit wneh the currneeb twtnee

the electrodes is sua hcs to prudoec electrloysis adn consqeneuap trtlai nisuitalno of the

leectredo surface

To avoid thsi uncertianty, different msaeruing meohtds can eb lppaied (see 3.7, 3.8 and

aennD x):

)a c.a msaerumestne iwht a frequency hihg neough ot avoip dolraizatiofe nfects;

)b fruo ro six elcertode msaerumenest iwth separated currnert tsnaporting nad topential

msaerunig elcertosed;

)c niudevitc or apaccievit measruements by coilpueb gnwtnee htele ecrtloytic ocudnotcr nad

the electricla measuriric gnctiu throunon hg-cdnoucvite meaid

5 egaP

2002:3−64706 NE

.32

E

j =

κ

hwree

t roc ehorrseopidngn seristivitu ynit, mmhoge c reptneimteer (M Ω cm)

1 µ S ⋅ mc 1– 01 = 4– S ⋅ m 1–

.33

X

L

=

llec κ

the qetaunoi:

κ = Kecll× G

hwree

.34

polrazitaoin

leectredo surface

aennD x):

)b fruo ro six elcertode msaerumenest iwth separated currnert tsnaporting nad topential

5 egaP

2002:3−64706 NE

3.2 electrolytic conductivity

E

j =

κ

where

E is the electric field strength, in V⋅m–1 The unit of electrolytic conductivity, κ, is siemens per metre (S⋅m–1) Electrolytic resistivity is the reciprocal of electrolytic conductivity with the unit of ohmmeter (Ω⋅m)

or the corresponding resistivity unit, megohm c reptneimteer (M Ω cm)

1 µ S ⋅ cm –1 10 = –4 S ⋅ m –1

3.3 cell constant of the sensor unit

X

L

=

cell κ

It is usual to measure electrolytic conductivity by means of cells without a uniform cross-section, in which case the Kcell should be determined by means of a reference solution of known electrolytic conductivity

The relationship between electrolytic conductance and electrolytic conductivity is defined by the equation:

κ = Kcell× G

where

NOTE 2 The cell constant will normally have a constant value over a stated range (see 4.1) Outside this range, it should be expected that polarization or other effects will produce errors (see 3.4 and annex D).

3.4 polarization

effect which occurs at electrode surfaces in an electrolytic solution when the current between the electrodes is such as to produce electrolysis and consequent partial insulation of the electrode surface

To avoid this uncertainty, different measuring methods can be applied (see 3.7, 3.8 and annex D):

b) four or six electrode measurements with separated current transporting and potential measuring electrodes;

c) inductive or capacitive measurements by coupling between the electrolytic conductor and the electrical measuring circuit through non-conductive media

5 egaP

60746−3:2002 NE

.32

E

j =

κ

hwree

1 µ S ⋅ mc 1– 01 = 4– S ⋅ m 1–

.33

X

L

=

llec κ

the qetaunoi:

κ = Kecll × G

hwree

.34

polrazitaoin

leectredo surface

aennD x):

)b fruo ro six elcertode measurements iwth separated currnert tsnaporting nad topential

5 egaP

2002:3−64706 NE

3.2

E

j =

κ

where

1 µ S ⋅ cm –1 = 01 4– S ⋅ m –1

3.3

X

L

=

cell κ

the equation:

κ = Kcell × G

where

3.4

polarization

electrode surface

annex D):

5 egaP

60746−3:2002 NE

3.2

E

j =

κ

where

NOTE In practical use, the most commonly employc deocudntivity unit is microsiemens per centimetre ( µ S ⋅ cm –1 )

1 µ S ⋅ cm –1 = 10 –4 S ⋅ m –1

3.3

X

L

=

cell κ

the equation:

κ = Kcell× G

where

3.4

polarization

electrode surface

annex D):

Page 5

EN 60746−3:2002

.32 leectroltyic ocndutcvitiy

E

j =

κ

hwree

E is htele ectric leifts drengtni ,h V⋅m1– Tnu ehit fo lecertolytic conductivtiy, κ, si siemneep sr metre (S⋅m1–.) elEctrloytci reisstivity is hte recirpcoal fo elcertloytic codncutivity iwth htnu eit fo ohmmrete (⋅Ω)m

ETON In carptical su,e thm eost commlnoy employed cocudntivity inut is micrsoiemsne c reptneimte( er µ S ⋅ mc –1 )

1 µ S ⋅ mc 1– = 01 4– S ⋅ m 1–

.33 cell consato tnf hte sesnor tinu

X

L

=

llec κ

tI si suual ot msaerue lecertolytic conductivtiy by means fo cesll iwhtout inu aform crsos-estcoin, ni which acse the Kecll uohseb dl edetrminde by means of r aerefence soluitno of knowe nlcertloytic codncutivity

The relaitnoship wtebeen electrloytic coudnatcncdna e leectrolytc cionductivity is edenifd by the qetaunoi:

κ = Kecll× G

hwree

NOET 2 hTe cec llonsatnt wlli normayll have a consatnt vaule over a stated range (see 4.1)uO stdie htsi range, it sdluoh e ebxpectt dehta loprazitanoi ro toehfe rfects wp llirocude reorsr s(.3 eena 4na denx )D.

.34 polrazitaoin

eefftc which occurs ta leectrode surfaces na ni electrloytic ulosnoit wneh the currneeb twtnee the electrodes is sua hcs to prudoec electrloysis adn consqeneuap trtlai nisuitalno of the leectredo surface

To avoid thsi uncertianty, different msaeruing meohtds can eb lppaied (see 3.7, 3.8 and aennD x):

)b fruo ro six elcertode msaerumenest iwth separated currnert tsnaporting nad topential msaerunig elcertosed;

)c niudevitc or apaccievit measruements by coilpueb gnwtnee htele ecrtloytic ocudnotcr and the electricla measuriric gnctiu throunon hg-cdnoucvite meaid

5 egaP

−647063:2002 NE

.32

E

j =

κ

hwree

1 µ S ⋅ mc 1– = 10 4– S ⋅ m 1–

.33

X

L

=

llec κ

the qetaunoi:

κ = Kecll× G

hwree

.34

polrazitaoin

leectredo surface

aennD x):

)b fruo ro six elcertode measurements iwth separated currnert tsnaporting nad topential

5 egaP

2002:3−64706 NE

E

j =

κ

where

1 µ S ⋅ cm –1 10 = –4 S ⋅ m –1

X

L

=

cell κ

κ = Kcell× G

where

5 egaP

60746−3:2002 NE

E

j =

κ

where

or the corresponding resistivity unit, megohm c reptneimteer M( Ω mc)

1 µ S ⋅ cm –1 = 10 –4 S ⋅ m –1

X

L

=

cell κ

κ = Kcell× G

where

Page 5

EN 60746−3:2002

E

j =

κ

hwree

ETON In carptical su,e thm eost commlnome ylpyoc deocudntivity inut is micrsoiemsne c reptneimte( er µ S ⋅ mc –1 )

t roc ehorrseopidngn seristivitu ynit, megohm per centimetre M( Ω mc)

1 µ S ⋅ mc 1– = 01 4– S ⋅ m 1–

X

L

=

llec κ

tI si suual ot msaerue lecertolytic conductivtiy by means fo cesll iwhtout inu aform crsos-estcoin, ni which acse the Kecll uohseb dl edetrminde by means of r aerefence soluitno of knowe nlcertloytic codncutivity

The relaitnoship wtebeen electrloytic coudnatcncdna e leectrolytc cionductivity is edenifd by the qetaunoi:

κ = Kecll× G

hwree

ETON 1 In carptical su,e Kcell is larenegly exprsesde in cm 1– , κ ni µ S ⋅ mc 1– nad G ni µ S (s.3 ee2).

NOET 2 hTe cec llonsatnt wlli normayll have a consatnt vaule over a stated range (see 4.1)uO stdie htsi range, it sdluoh e ebxpectt dehta loprazitanoi ro toehfe rfects wp llirocude reorsr s(.3 eena 4na denx )D.

)c niudevitc or apaccievit measruements by coilpueb gnwtnee htele ecrtloytic ocudnotcr and the electricla measuriric gnctiu throunon hg-cdnoucvite meaid

5 egaP

−647063:2002 NE

3.2

E

j =

κ

where

1 µ S ⋅ cm –1 01 = –4 S ⋅ m –1

3.3

X

L

=

cell κ

the equation:

κ = Kcell× G

where

3.4

polarization

electrode surface

annex D):

a) c.a measurements with a frequency high enough to avoid polarization effects;

b) four or six electrode msaerumenest with separated current transporting and potential

Page 5

EN 60746−3:2002

E

j =

κ

hwree

1 µ S ⋅ mc 1– 10 = –4 S ⋅ m 1–

X

L

=

llec κ

tI si suual ot msaerue lecertolytic conductivtiy by means fo cesll iwhtout inu aform crsos-estcoin, ni which acse the Kecll uohseb dl edetrminde by means of r aerefence soluito nof knowe nlcertloytic codncutivity

The relaitnoship wtebeen electrloytic coudnatcncdna e leectrolytc cionductivity is edenifb dy the qetaunoi:

κ = Kecll× G

hwree

NOET 2 hTe cec llonsatnt wlli normayll have a consatnt vaule over a stated range (see 4.1)uO stdie htsi range, ti sdluoh e ebxpectt dehta loprazitanoi ro toehfe rfects wp llirocude reorsr s(.3 eena 4na denx )D.

)a a.c msaerumestne iwht a frequency hihg neough ot avoip dolraizatiofe nfects;

)c niudevitc or apaccievit measruements by coilpueb gnwtnee htele ecrtloytic ocudnotcr nad the electricla measuriric gnctiu throunon hg-cdnoucvite meaid

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E

j =

κ

hwree

ETON In carptical su,e thm eost commlnome ylpyoed conductivity inut is micrsoiemsne c reptneimte( er µ S ⋅ mc 1– )

t roc ehorrseopidngn seristivitu ynit, mmhoge per ctneimteer M( Ω mc)

1 µ S ⋅ mc 1– 01 = 4– S ⋅ m 1–

X

L

=

llec κ

tI si suual ot msaerue lecertolytic conductivtiy by means fo cesll iwhtout inu aform crsos-estcoin, ni which acse the Kecll uohseb dl edetrminde by means of r aerefence soluito nof knowe nlcertloytic codncutivity

The relaitnoship wtebeen electrloytic coudnatcncdna e leectrolytc cionductivity is edenifb dy the qetaunoi:

κ = Kecll× G

hwree

NOET 2 hTe cec llonsatnt wlli normayll have a consatnt vaule over a stated range (see 4.1)uO stdie htsi range, ti sdluoh e ebxpectt dehta loprazitanoi ro toehfe rfects wp llirocude reorsr s(.3 eena 4na denx )D.

)a a.c msaerumestne iwht a frequency hihg neough ot avoip dolraizatiofe nfects;

)c niudevitc or apaccievit measruements by coilpueb gnwtnee htele ecrtloytic ocudnotcr nad the electricla measuriric gnctiu throunon hg-cdnoucvite meaid

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E

j =

κ

where

NOTE In practical use, the most commonlme ylpyoc deonductivity unit is microsiemens per centimetre ( µ S ⋅ mc –1 )

or the corresponding resistivitu ynit, megohm per centimetre (M Ω cm)

1 µ S ⋅ cm –1 10 = –4 S ⋅ m –1

X

L

=

cell κ

κ = Kcell× G

where

a) c.a measurements with a frequency high enough to avoid polarization effects;

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067-643  EI:C002(2)E – 7 –

In each case, the relationship between the electrolytic conductivity and the measured output quantity is established by the cell constant

3.5

temperature coefficient

relative increase (or decrease) of the electrolytic conductivity of a solution per kelvin temperature change The temperature coefficient is dependent on the reference temperature and the nature of the solution

The following approximate equation can be applied for strong electrolyte solutions where

κ > 10–4 S⋅m–1 (1 µS⋅cm–1)

( + ∆t)

×

= κ α

where

κt is the electrolytic conductivity at temperature t;

κtr is the electrolytic conductivity at reference temperature tr;

∆t is the temperature difference t − tr;

α is the temperature coefficient

In practice, this formula is sufficiently accurate over a small temperature range For large temperature ranges, it is usually necessary to add higher terms of a polynomial series (such

as β(∆t)2+ γ(∆t)3+ ) to the above equation, to obtain sufficient accuracy The percentage temperature coefficient, which is the percentage relative deviation per kelvin from the reference value κtr, is often used so that

α (%) = 100 α NOTE The manufacturer’s literature should be consulted for details of sample temperature compensation technique(s) applied.

3.6

simulator

a series of non-inductive resistors (preferably step-variable, e.g., a decade resistance box), used for the performance tests of conductimetric electronic units, simulating two- and three-electrode sensors

NOTE The minimum step should preferably be 0,01 R, where R is the reciprocal value of the nominal full range

conductivity value Analogously, the highest resistance value should correspond to the lower limit of the measuring

range: if the range begins at zero, the resistance value should be at least 10 R for testing at 10 % of the range.

For multi-electrode sensor simulator design, the manufacturer must be consulted

The temperature sensor may be simulated by another variable precision resistor, e.g., a variable decade resistance box

3.7

cell capacitance

produced by the electrostatic field existing between the sensor's measuring electrodes due to the high dielectric constant of water Its value is inversely proportional to the cell constant and expressed by the approximate relationship:

cell

7

K

where

Ccell is the cell capacitance, in picofarads (pF: 1 pF = 10–12 F);

Kcell is the cell constant, in cm–1;

Ccell may disturb low conductivity measurements made with two- or three-electrode cells

when too high a frequency is used The effect can be reduced by means of phase discrimination within the electronic unit

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EN 60746−3:2002

ψ

In aech caseht ,r eeitalnosheb piwtnee hte electrloytci coudnivitcty dna hte measurde uouptt qnautity is estilbasdeh by teh llec nocsnatt

.35

tepmertaure oceffiicnet

relavite inrcaees (or edrcaese) of the electrloytic dnocucvitity of a soluitp noer kenivl tempertaure cnaheg The etmpertaure coeiffneici ts ednepnedno t htr eeefrecne etmperutare aht dne nature of tlos ehunoit

Teh folloiwgn parpxomieta equatoin cab ne applif deor strogn elcertolyte soultions hwree

κ 1 >04– S⋅m1– 1( µS⋅mc1–)

) + ∆t(

×

= κ α

hwree

κt is hte electrloytic coudntcivity ta etmperutare t;

κrt is htele ectrloytic coudntcivity ta reefrencet emperutare rt;

∆t si the temreptarud eiffercnee t − rt;

α si the temreptaruc eofeficient

nI rpcaciteht ,si formlusi a sufficinetly cacurate ovre s amlal temreptarur eagne For large tempertaure rgnaes, ti is suually enceassry dda ot ehgihr termo sf lop aynomais leries (such

sa β(∆t)2+ γ(∆t)3 + ) ot thba eove equatio,n to obtani sufficient cacuracy The repcetngae metrepatruc eofeficient, whcih si the percentage relatiev edvitaion rep kelvin frmo hte reefrencv eaule κrt, si foetn sude so thta

α (%) 1 =00 α ETON ehT mfunacature’rs litertas eruhluoc eb dosnlutef dor tedials fo sample temtarepurc eomsneptaion tecinhque(s) alppi.de

.36

isumlator

a series of non-iudnevitc resiotsrs (preefrlbay stpe-vralbai,e e.ga , decdar eeisstance ob)x, usde ofr teh eprformance ettss of conductimertic elcetrinoc inuts, simualgnit wt-o adn htre-e elcertode sesnros

ETON m ehTiinmum tss peluohd rpfeerbaly be ,001 R, whree R is teh reciprcola laveu fo thmon eilan full rgnae

ccudnotiivty lav.eu Anlaosuogly, tih ehhgset seristcnae avls euhluoc dorrsept dnoo tl ehowel rimit fo tm ehsaeirung

nar:eg if teh aregn ebigsn ta ezro, teh seristcnae lavs euhluod ta eb lsaet 01 R fot restinta g 01 % fo thr egna.e

For mutl-ielcertdoe sesnro simulator desing, hte mfunacaturer must be cosnuletd

The tempertaure nessor may be simualdet by natoehr varilbarp eecisoir neisstor.e ,.g, a avrielba decdar eesiatsncob e.x

.37

ecll pacactinace

prudoced by eht leectrostaitc leifd exisitgn ebwteet neh nessor's measurgni electrodes udot e hte hihg dielcertci cosntant fo awter Its vaule si vniersely rpporoitonal to tc ehell cosnattn nad xerpseseb dy hte approximate relatisnohip:

llec

7

K

hwree

Cecll si the cell capacitcna,e p niicofarasd (pF: Fp 1 01 =21– )F;

Kecll is thnoc llec estant, ni mc;1–

Cecll may sidtrub olc wodncuvitity msaerumenest made with tw-o or three-leecrtdoe cells

wneh too gihh a rfuqeneyc si usdeT he eefftc can r ebeudced by menas of ahpse idrcsimniitaw noiniht teh electrinou cnti

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3.8

leakage currents

a.c currents at the measuring frequency flowing from the cell electrodes to local conductive

parts in contact with the sample solution

They effectively alter the cell constant causing measuring uncertainties and arise principally in

symmetrical cells, i.e., with similar electrodes side by side

4 Procedure for specification

See clause 5 of IEC 60746-1, plus the following

4.1 Additional statements on sensor units

a) Type, i.e., flow-through, dip or insertion unit, number of electrodes, if electrodeless

whether inductive or capacitive cell (common types of cell are described in annex D)

b) Cell constant, tolerance and corresponding range of measurement (see 4.3a))

c) Type of temperature compensator (for example, Pt100)

d) Sensor dimensions, mounting and connection details

4.2 Additional statements on electronic units

a) Measuring frequency/frequencies

b) Cell constant adjustment range

c) Type of temperature compensator sensor to which the electronic unit can be connected

and maximum permitted resistance of compensator plus connection leads

d) Reference temperature adjustment range; if fixed, state temperature

e) Range of temperature coefficient adjustment and details of sample temperature

compensation that may be applied If fixed, state value

f) Installation details

4.3 Additional statements on complete analyzers

a) Measuring ranges (rated and effective)

NOTE Some analyzers employ concentration units, for example, mass % NaCl, g NaOH per litre, etc.

For such analyzers, the rated range should be specified on the measurement unit as well as the corresponding

conductivity at the rated reference temperature.

b) Reference temperature for the measurement

c) Installation details

5 Recommended standard values and ranges of influence quantities

affecting the performance of electronic units

See annex A of IEC 60746-1

6 Verification of values

See clause 6 of IEC 60746-1

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EN 60746−3:2002

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6.1 General aspects

The parameters required to be set in the electronic unit for the specific combination of the electronic unit and sensor shall be established These shall include

– the range to be measured and the units for display (if a display is fitted);

– the range and type of any transmitted output;

– the type of sample, i.e., a flow-through sample and its flow rate, or a static sample into which the sensor is immersed and its minimum depth;

– the type and range of sample temperature compensation for which verification is required,

if applicable

6.2 Calibration

For accurate calibration of a conductivity analyzer the following parameters are required for adjustment on the electronic unit:

a) the cell constant (see 3.3 and 4.2 b));

b) the reference temperature (see 4.2d));

c) the temperature coefficient or appropriate algorithm (see 4.2e))

NOTE The exact value of the cell constant can be determined using an appropriate calibration solution (see annex A).

6.3 Test solutions

Test solutions shall be applied in a manner suited to the design of the sensor

For flow-through sensors, the solutions shall be applied at a flow rate within the manu-facturer’s stated rated range

For sensors which can be immersed into test solutions, it is essential that the sensor unit is rinsed several times with water of negligible conductivity (in comparison with the range to be tested) after immersion in one solution prior to immersion in a fresh solution A good procedure is to keep a second container of each test solution concentration to be used for the final rinse prior to immersion in each respective accurate test solution

The immersion of sensor probes into containers of test solution exposed to air is not appropriate for measurements below 100 µS⋅cm–1

NOTE De-ionized water in an open container absorbs CO2; a typical equilibrium conductivity of approximately 0,9 µ S ⋅ cm –1 is eventually reached.

Examples of test solutions are tabulated in annex B

For low-conductivity solutions below about 100 µS⋅cm–1 (at 25 °C), it is essential that flowing solutions of appropriate conductivities are generated by continuous injection of, e.g., NaCl solutions into a pure water stream at a controlled flow rate Required concentrations may be determined by extrapolation of values in annex B

Pure water can only be generated by a circulatory de-ionization system: standard test solutions shall be generated from such water

Page 8

EN 60746−3:2002

Tiêu đề	Expression of Performance of Electrochemical Analyzers — Part 3: Electrolytic Conductivity
Trường học	British Standards Institution
Chuyên ngành	Electrochemical Analyzers
Thể loại	British Standard
Năm xuất bản	2002
Thành phố	London

Định dạng
Số trang	20
Dung lượng	0,99 MB