prEN 1434-2

Thermal energy meters - Part 2: Constructional requirements

This document specifies the constructional requirements for thermal energy meters. Thermal energy meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The thermal energy meter indicates the quantity of thermal energy in legal units.
Electrical safety requirements are not covered by this document.
Pressure safety requirements are not covered by this document.
Surface mounted temperature sensors are not covered by this document.
This document covers meters for closed systems only, where the differential pressure over the thermal load is limited.

Thermische Energiemessgeräte - Teil 2: Anforderungen an die Konstruktion

Dieses Dokument legt die Konstruktionsanforderungen für thermische Energiemessgeräte fest. Thermische Energiemessgeräte sind Messgeräte, die dazu bestimmt sind, die Energie zu messen, die in einem Wärmetauschkreislauf von einer als Wärmeträgerflüssigkeit bezeichneten Flüssigkeit aufgenommen (Kühlung) oder abgegeben (Heizung) wird. Das thermische Energiemessgerät zeigt die Menge der thermischen Energie in gesetzlichen Einheiten an.
Anforderungen an die elektrische Sicherheit sind nicht Gegenstand dieses Dokuments.
Anforderungen an die Drucksicherheit sind nicht Gegenstand dieses Dokuments.
Oberflächenmontierte Temperaturfühlern sind nicht Gegenstand dieses Dokuments.
Dieses Dokument behandelt nur Messgeräte für geschlossene Systeme, bei denen der Differenzdruck über die thermische Last begrenzt ist.

Compteurs d'énergie thermique - Partie 2 : Prescriptions de fabrication

Le présent document spécifie les prescriptions de fabrication relatives aux compteurs d’énergie thermique. Les compteurs d’énergie thermique sont des instruments destinés à mesurer l’énergie thermique qui, dans un circuit d’échange thermique, est absorbée (refroidissement) ou cédée (chauffage) par un liquide appelé « liquide caloporteur ». Le compteur d’énergie thermique fournit la quantité d’énergie thermique en unités de mesure légales.
Le présent document ne traite pas des prescriptions de sécurité électrique.
Le présent document ne traite pas des prescriptions de sécurité relative à la pression.
Le présent document ne traite pas des sondes de température montées en surface.
Le présent document couvre les compteurs pour les systèmes fermés uniquement, où la pression différentielle dans la charge thermique est limitée.

Merilniki toplote - 2. del: Konstrukcijske zahteve

General Information

• Status: Not Published
• ICS: 17.200.20 - Temperature-measuring instruments
• Technical Committee: CEN/TC 176 - Heat meters
• Drafting Committee: CEN/TC 176/WG 2 - Heat Meters - Requirements, test methods and technical editing
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Due Date: 16-Dec-2021
• Completion Date: 16-Dec-2021
• Directive: 2014/32/EU - Directive 2014/32/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of measuring instruments
• Mandate: M/541 - [C(2015)8558] Standardization request in support of the implementation of Directive 2014/32/EU on measuring instruments
• Ref Project: oSIST prEN 1434-2:2020 - Thermal energy meters - Part 2: Constructional requirements

RELATIONS

• Revised: EN 1434-2:2015+A1:2018 - Thermal energy meters - Part 2: Constructional requirements
• Effective Date: 12-Jun-2019

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 1434-2:2020
01-november-2020
Merilniki toplote - 2. del: Konstrukcijske zahteve
Thermal energy meters - Part 2: Constructional requirements
Thermische Energiemessgeräte - Teil 2: Anforderungen an die Konstruktion
Compteurs d'énergie thermique - Partie 2 : Prescriptions de fabrication
Ta slovenski standard je istoveten z: prEN 1434-2
ICS:
17.200.20 Instrumenti za merjenje Temperature-measuring
temperature instruments
oSIST prEN 1434-2:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 1434-2:2020
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oSIST prEN 1434-2:2020
DRAFT
EUROPEAN STANDARD
prEN 1434-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2020
ICS 17.200.20 Will supersede EN 1434-2:2015+A1:2018
English Version
Thermal energy meters - Part 2: Constructional
requirements

Compteurs d'énergie thermique - Partie 2 : Thermische Energiemessgeräte - Teil 2:

Prescriptions de fabrication Anforderungen an die Konstruktion

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 176.

If this draft becomes a European Standard, CEN 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.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1434-2:2020 E

worldwide for CEN national Members.
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prEN 1434-2:2020
Contents Page

European foreword ....................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 6

4 Temperature sensors .................................................................................................................................... 6

4.1 General ................................................................................................................................................................ 6

4.2 Mechanical design ........................................................................................................................................... 6

4.2.1 General ................................................................................................................................................................ 6

4.2.2 Materials of temperature probe sheath and pocket ........................................................................... 6

4.2.3 Dimensions of direct mounted short probes - Type DS ..................................................................... 7

4.2.4 Dimensions of direct mounted long probes - Type DL ...................................................................... 7

4.2.5 Dimensions of pocket mounted long probes - Type PL ..................................................................... 8

4.2.6 Dimensions of temperature pocket .......................................................................................................... 9

4.2.7 Design of short probes with respect to installation......................................................................... 10

4.2.8 Design of long probes with respect to installation .......................................................................... 10

4.3 Platinum temperature sensor ................................................................................................................. 11

4.3.1 Specialized definitions for 2 wire temperature probes ................................................................. 11

4.3.2 Resistance characteristics ........................................................................................................................ 12

4.3.3 Signal leads ..................................................................................................................................................... 12

4.3.4 Temperature sensors for the 2-wire method .................................................................................... 13

4.3.5 Temperature sensors for the 4-wire method .................................................................................... 13

4.3.6 Thermal response time .............................................................................................................................. 13

4.3.7 Qualifying immersion depth of a temperature sensor ................................................................... 13

4.4 Other temperature sensors ...................................................................................................................... 13

5 Flow sensors .................................................................................................................................................. 14

5.1 Maximum admissible working pressure, PS in bar ......................................................................... 14

5.2 Sizes and dimensions .................................................................................................................................. 14

5.3 Test signal output......................................................................................................................................... 15

5.4 Adjusting device ........................................................................................................................................... 15

6 Calculators ...................................................................................................................................................... 16

6.1 Terminals - specification and identification ...................................................................................... 16

6.1.1 General ............................................................................................................................................................. 16

6.1.2 Terminals for signal leads......................................................................................................................... 16

6.1.3 Terminals for connection to the mains supply .................................................................................. 17

6.2 Batteries .......................................................................................................................................................... 17

6.3 Dynamic behaviour ..................................................................................................................................... 18

6.4 Test signal output......................................................................................................................................... 18

6.5 24 h interruption in supply voltage ....................................................................................................... 18

7 Complete meter ............................................................................................................................................ 18

8 Interfaces between sub-assemblies ...................................................................................................... 19

8.1 General ............................................................................................................................................................. 19

8.2 Definitions for pulse device interfaces ................................................................................................. 19

8.2.1 General ............................................................................................................................................................. 19

8.2.2 Electrical connection .................................................................................................................................. 19

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8.2.3 Classification of pulse output devices ................................................................................................... 19

8.2.4 Timing and electrical parameters for pulse output devices (other than test signals) ........ 20

8.2.5 Classification of pulse input devices ...................................................................................................... 20

8.2.6 Timing and electrical parameter for pulse input devices .............................................................. 21

8.2.7 Compatibility .................................................................................................................................................. 21

9 Marking and security seals........................................................................................................................ 22

9.1 Marking ............................................................................................................................................................ 22

9.1.1 General ............................................................................................................................................................. 22

9.1.2 Temperature sensor pairs ......................................................................................................................... 22

9.1.3 Pockets ............................................................................................................................................................. 22

9.1.4 Flow sensor ..................................................................................................................................................... 22

9.1.5 Calculator......................................................................................................................................................... 23

9.1.6 Complete meter ............................................................................................................................................. 23

9.2 Sites for marking ........................................................................................................................................... 24

9.3 Security seals .................................................................................................................................................. 24

Annex A (informative) Examples of temperature sensors ............................................................................ 25

Annex B (normative) Input and output test signals ........................................................................................ 37

Annex C (informative) Low voltage power supply for the thermal energy meters and their

subassemblies ................................................................................................................................................ 39

C.1 Remote supply ............................................................................................................................................... 39

C.1.1 Voltage (DC or AC) ........................................................................................................................................ 39

C.1.2 Current available .......................................................................................................................................... 39

C.1.3 Cabling requirements ................................................................................................................................. 39

C.2 Local external DC supply ............................................................................................................................ 39

C.2.1 Voltage .............................................................................................................................................................. 39

C.2.2 Other data ........................................................................................................................................................ 39

C.3 Power supply specifications ..................................................................................................................... 40

Annex ZA (informative) Relationship between this European Standard and the essential

requirements of Directive2014/32/EU aimed to be covered ...................................................... 41

Bibliography ................................................................................................................................................................. 42

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European foreword

This document (prEN 1434-2:2020) has been prepared by Technical Committee CEN/TC 176 “Thermal

energy meters”, the secretariat of which is held by SIS.
This document is currently submitted to the CEN Enquiry.
This document supersedes EN 1434-2:2015+A1:2018.
EN 1434-2, Thermal energy meters consists of the following parts:
— Part 1: General requirements
— Part 2: Constructional requirements
— Part 3: Data exchange and interfaces
— Part 4: Pattern approval tests
— Part 5: Initial verification tests
— Part 6: Installation, commissioning, operational monitoring and maintenance
In comparison to EN 1434-2:2015+A1:2018, the following changes have been made:

— Figure A.10 “Threaded pipe fitting G1/2B, G3/4B, G1B, G1 1/4B and G1 1/2B sizes” was updated;

— in subclause 4.2.2 “Materials of temperature probe sheath and pocket” another suitable material was

added.

This document has been prepared under a standardization request given to CEN by the European

Commission and the European Free Trade Association, and supports essential requirements of

EU Directive(s).

For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this

document.
EN 1434-3 is maintained by CEN/TC 294.
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1 Scope

This document specifies the constructional requirements for thermal energy meters. Thermal energy

meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed

(cooling) or given up (heating) by a liquid called the heat-conveying liquid. The thermal energy meter

indicates the quantity of thermal energy in legal units.
Electrical safety requirements are not covered by this document.
Pressure safety requirements are not covered by this document.
Surface mounted temperature sensors are not covered by this document.

This document covers meters for closed systems only, where the differential pressure over the thermal

load is limited.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

EN 1092-1, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN

designated — Part 1: Steel flanges

EN 1092-2, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN

designated — Part 2: Cast iron flanges

EN 1092-3, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN

designated — Part 3: Copper alloy flanges
prEN 1434-1:2020, Thermal energy meters — Part 1: General requirements
prEN 1434-3:2020, Thermal energy meters — Part 3: Data exchange and interfaces
prEN 1434-4:2020, Thermal energy meters — Part 4: Pattern approval tests

EN 60751:2008, Industrial platinum resistance thermometers and platinum temperature sensors

(IEC 60751:2008)

EN 60947-5-6, Low-voltage switchgear and controlgear — Part 5-6: Control circuit devices and switching

elements — DC interface for proximity sensors and switching amplifiers (NAMUR) (IEC 60947-5-6)

EN ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,

tolerances and designation (ISO 228-1)

ISO 4903, Information technology — Data communication — 15-pole DTE/DCE interface connector and

contact number assignments
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3 Terms and definitions

For the purposes of this document, the terms and definitions given in prEN 1434-1:2020 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
4 Temperature sensors
4.1 General

The temperature sensor sub-assembly shall consist of platinum resistance temperature sensors selected

as matched pairs.

Other types of temperature sensor pairs may be used, where the sub-assembly consists, inseparably, of

temperature sensors and calculator.
The maximum admissible working pressure shall be declared by the manufacturer.

Where no dimensional tolerance is specified, the values shall be taken from Table 1.

Table 1 — Tolerances

Dimension 0,5 up to 3 over 3 up to 6 over 6 up to 30 over 30 up to over 120 up to 400

120
Tolerance ±0,2 ±0,3 ±1 ±1,5 ±2,5
4.2 Mechanical design
4.2.1 General

For pipe sizes up to and including DN 250, 3 different temperature sensor types are standardized:

— direct mounted short probes - Type DS;
— direct mounted long probes - Type DL;
— pocket mounted long probes - Type PL.

Types PL and DL can be either head probes or have permanently connected signal leads. Type DS shall

have permanently connected signal leads only.
4.2.2 Materials of temperature probe sheath and pocket

The temperature pocket and the protective sheath of direct mounted probes shall be of a material that is

adequately strong and resistant to corrosion and has the requisite thermal conductivity.

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Examples of suitable materials are:
EN 10088-3 – X2 Cr Ni Mo 17 13 2 (also known as W.nr. 1.4404)
EN 10088-3 – X6 Cr Ni Mo Ti 17 12 2 (also known as W.nr. 1.4571)
4.2.3 Dimensions of direct mounted short probes - Type DS
The dimensions shall be as given in Figure 1.

Further non-normative information is given in Annex A, Figure A.1. The qualifying immersion depth shall

be 20 mm – or less if so specified by the manufacturer.
Dimensions in millimetres
Key
1 temperature sensing element
2 protective sheath
3 sealing ring
4 ejection device
A: < 15 mm
B: = 27,5 mm or = 38 mm or 60 mm
Figure 1 — Temperature probes type DS
4.2.4 Dimensions of direct mounted long probes - Type DL
The dimensions shall be as given in Figure 2.
Further information is given in Annex A, Figures A.2 and A.3.

The qualifying immersion depth shall be 50 % of the length B – or less if so specified by the manufacturer.

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Dimensions in millimetres
Key
1 temperature sensing element 4 outline of head probe
2 protective sheath 5 outline of permanently connected signal lead probe
3 sealing surface 6 inlet for signal cable – ø ≤ 9 mm
G 1/2 B thread in accordance with EN ISO 228-1
A: < 30 mm or ≤ 50 mm for Pt1000
Alternative lengths
B C (head probe only)
85 105
120 140
210 230
Figure 2 — Temperature probes type DL (head or cable)
4.2.5 Dimensions of pocket mounted long probes - Type PL
The dimensions shall be as given in Figure 3.
Further information is given in Annex A, Figures A.4 and A.5.

The qualifying immersion depth shall be 50 % of the length B for the shortest pocket specified – or less if

so specified by the manufacturer.
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Dimensions in millimetres
Key
A < 30 mm or ≤ 50 mm for Pt 1 000
Alternative lengths
B (head probe only)
105
140
230

1 temperature sensing element 3 outline of permanently connected signal lead probe

2 outline of head probe 4 inlet for signal cable – ø ≤ 9 mm
Corresponding to c11 in EN ISO 286-2, rounded to 2 decimals
Figure 3 — Temperature probes - Type PL (head or cable)
4.2.6 Dimensions of temperature pocket

The temperature pocket is designed for use with type PL temperature probes only. It is designed to be

capable of being inserted through a pipe wall to which has been externally brazed or welded a boss (see

Annex A, Figure A.9) and in this respect only, it is interchangeable with a direct mounted long probe of

corresponding insertion length. The dimensions shall be as given in Figure 4.
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Dimensions in millimetres
Key
1 sealing face
2 probe clamping screw with provision for security sealing
a Corresponding to H11 in EN ISO 286-2 rounded to 2 decimals
G 1/2 B thread in accordance with EN ISO 228-1
Alternative lengths
C D
85 ≤ 100
120 ≤ 135
210 ≤ 225
Figure 4 — Temperature pocket
4.2.7 Design of short probes with respect to installation

The sensor shall be mounted perpendicular to the flow and with the sensing element inserted to at least

the centre of the pipe.

For internal pressures up to 16 bar, the sensor shall be designed to fit in a pipe fitting (see Annex A,

Figure A.10).
4.2.8 Design of long probes with respect to installation

The sensor shall be mounted with the sensing element inserted to at least the centre of the pipe.

The sensor shall be designed to fit in the following types of installation, (for internal pressures up to

PN 16):
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a) in a pipe DN 50 mounted with the tip pointing into the flow in a bend (see Annex A, Figure A.12 b),

using welded-in boss (see Annex A, Figure A.9);

b) in a pipe DN 50 mounted at an angle 45° to the direction of the flow with the tip pointing into the

flow (see Annex A, Figure A.12 c), using a welded-in boss (see Annex A, Figure A.9);

c) in a pipe DN 65 to DN 250, mounted perpendicular to the flow (see Annex A, Figure A.12 d), using a

welded-in boss (see Annex A, Figure A.9).
4.3 Platinum temperature sensor
4.3.1 Specialized definitions for 2 wire temperature probes
Key
R temperature sensing element resistance 1 temperature sensing element
internal wire resistance 2 protective sheath
R signal lead resistance 3 mounting thread
4 signal leads
Figure 5 — Temperature probe with permanently connected signal leads
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Key
R temperature sensing element resistance 1 temperature sensing element
R internal wire and terminals resistance 2 protective sheath
3 mounting thread
4 signal leads
Figure 6 — Head sensor temperature probe
4.3.2 Resistance characteristics

The calibration of temperature sensors shall be traceable to national temperature standards. The

intermediate values of the thermal energy meter temperature sensor shall be interpolated using

Formula (1) defined in EN 60751:2008, 4.1 as follows:
R R 1++At Bt (1)
( )
t 0
where

is the resistance value at temperature t in Ω (excluding cable resistance - see Figures 5 and

6);

R is the resistance value at temperature 0 °C in Ω (base value) (excluding cable resistance);

−3 -1
is 3,908 3 × 10 °C ;
−7 -2
is −5,775 × 10 °C .

NOTE It is assumed that the national temperature standards are established with reference to ITS-90 - The

International Temperature Scale of 1990.
4.3.3 Signal leads

For signal leads, leads with strands can be used, or in the case of head probes, solid wires. The lead ends

shall be precisely trimmed, if strands are used (e.g. by lead end sleeves). Solder-coating of the lead ends

to prevent splicing is not permissible.

A soldered joint to connect the temperature probe signal lead to the calculator is only permitted in the

case of non-interchangeable temperature probes.

For screened cables for temperature sensors there shall be no connection between the screen and the

protecting sheet.
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To ensure best performance and measurement stability the 4-wire method and Pt 100 or Pt 500-

platinium resistance temperature sensors should be used.
4.3.4 Temperature sensors for the 2-wire method

The length and cross sectional area of signal leads of paired resistance sensors of separable sub-

assemblies shall be equal.

The length of the signal lead as supplied by the manufacturer shall not be changed.

The length shall be within the values given in Table 2.
Table 2 — Maximum lengths of leads for Pt 100 temperature sensors
Lead cross section Max. length for Pt 100
0,22 2,5
0,50 5,0
0,75 7,5
1,50 15,0

For sensors of higher resistances the limiting value can be extended proportionally.

NOTE The values given in Table 2 have been obtained in the following manner:

It is assumed, that the difference in temperature of the leads does not exceed one third of the temperature

difference between inlet and outlet pipes.

The maximum permissible length of lead for each lead cross section was then calculated, having decided

that the error created may not be allowed to exceed 0,2 times the maximum permissible error of the

temperature probe pair and using the knowledge of the different resistances created by the temperature

differences between the inlet and outlet leads.

The influence of the length of a signal lead can be neglected, if the total resistance of a lead for a Pt 100

temperature sensor does not exceed two times 0,2 Ω.
4.3.5 Temperature sensors for the 4-wire method

If the cable length requirements in 4.3.4 cannot be fulfilled, the 4-wire method shall be used.

The connections shall be clearly identifiable so that they cannot be confused.
2 2

A cross-section of 0,5 mm is recommended for head sensors and a minimum cross-section of 0,14 mm

for cable sensors.
4.3.6 Thermal response time

The manufacturer shall declare the temperature sensor response time τ as defined in EN 60751:2008,

0,5
3.11 using the test method in EN 60751:2008, 6.5.2.
4.3.7 Qualifying immersion depth of a temperature sensor

The manufacturer shall declare the qualifying immersion depth as defined in prEN 1434-4:2020, 7.4.4.1.

4.4 Other temperature sensors

Other types of temperature sensors are permissible, but shall be tested as part of the calculator.

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5 Flow sensors
5.1 Maximum admissible working pressure, PS in bar
The maximum admissible working pressure shall be declared by the manufacturer.
5.2 Sizes and dimensions

The flow sensor is designated either by the thread size of the end connections or by the nominal diameter

of the flange. For each flow sensor size there is a corresponding value of the permanent flow rate q and

a set of lengths as given in Tables 3 and 4.

The values in Table 3 apply to the connecting screw and/or the flange and the overall lengths.

For sizes larger than DN 250 the flow sensor dimensions are not standardized.
Table 3 — Preferred dimensions
Overall Flanged Flanged Overall
Threaded Overall Threaded Threaded
length connection connection length
end length end end
m /h
connection mm connection connections
mm DN DN mm
0,6 110 G 3/4 B 15 190 G 1 B 20
1,0 130 G 3/4 B 15 190 G 1 B 20 110 G 3/4 B
1,5 165 G 3/4 B 15 190 G 1 B 20 110 G 3/4 B
2,5 190 G 1 B 20 130 G 1 B
3,5 260 G 1 1/4 B 25 150 G 1 1/4 B
6,0 26
...