EN ISO 6145-7:2018

Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2018)

ISO 6145 is a series of documents dealing with various dynamic methods used for the preparation of calibration gas mixtures. This document specifies a method for continuous preparation of calibration gas mixtures, from nominally pure gases or gas mixtures by use of thermal mass-flow controllers. The method is applicable to preparation of mixtures of non-reacting species, i.e. those which do not react with any material of construction of the flow path in the thermal mass-flow controller or the ancillary equipment.
If this method is employed for preparation of calibration gas mixtures the optimum performance is as follows: the relative expanded measurement uncertainty U, obtained by multiplying the standard uncertainty by a coverage factor k = 2, is not greater than 2 %.
If pre-mixed gases are used instead of pure gases, mole fractions below 10−6 can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration.
The merits of the method are that a large quantity of the calibration gas mixture can be prepared on a continuous basis and that multi-component mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.
NOTE       Gas blending systems, based upon thermal mass-flow controllers, and some including the facility of computerization and automatic control, are commercially available.

Gasanalyse - Herstellung von Kalibriergasgemischen mit Hilfe von dynamischen Verfahren - Teil 7: Thermische Massendurchflussregler (ISO 6145-7:2018)

ISO 6145 ist eine Reihe von Dokumenten, die verschiedene dynamische Verfahren zur Herstellung von Kalibriergasgemischen behandeln. Dieses Dokument legt ein Verfahren zur kontinuierlichen Herstellung von Kalibriergasgemischen aus nominell reinen Gasen oder Gasgemischen mithilfe thermischer Massendurchflussregler fest. Das Verfahren wird zur Herstellung von Gemischen aus nicht reagierenden Gasspezies verwendet, d. h. solcher, die nicht mit den Materialien, die zur Ausführung des Durchflussweges im thermischen Massendurchflussregler oder der Zusatzausrüstung verwendet wurden, reagieren.
Wird dieses Verfahren zur Herstellung von Kalibriergasgemischen angewendet, ist die optimale Leistung wie folgt: die relative erweiterte Messunsicherheit U, die durch Multiplizieren der Standardunsicherheit mit einem Überdeckungsfaktor von k = 2 erhalten wird, ist nicht größer als 2 %.
Werden anstelle reiner Gase Gasvorgemische verwendet, können Molfraktionen unter 10−6 erreicht werden. Die Messung des Massenstroms ist nicht absolut und für den Massendurchflussregler ist eine unabhängige Kalibrierung erforderlich.
Die Vorzüge dieses Verfahrens bestehen darin, dass eine große Menge des Kalibriergasgemisches kontinuierlich hergestellt werden kann und dass Mehrkomponentengemische bei entsprechender Anzahl von thermischen Massestromreglern so einfach wie binäre Gemische hergestellt werden können.
ANMERKUNG   Gasmischsysteme auf der Grundlage thermischer Massendurchflussregler und einige Gasmisch-systeme, die die Möglichkeit einer Computersteuerung und automatischen Steuerung einschließen, sind im Handel erhältlich.

Analyse des gaz - Préparation des mélanges de gaz pour étalonnage à l'aide de méthodes dynamiques - Partie 7: Régulateurs thermiques de débit massique (ISO 6145-7:2018)

L'ISO 6145 est une série de documents qui traitent des diverses méthodes dynamiques utilisées pour la préparation des mélanges de gaz pour étalonnage. Le présent document spécifie une méthode de préparation en continu de mélanges de gaz pour étalonnage, à partir de gaz nominalement purs ou de mélanges de gaz, à l'aide de régulateurs thermiques de débit massique. La méthode s'applique à la préparation de mélanges de gaz non réactifs, c'est-à-dire des gaz qui ne réagissent avec aucun des matériaux utilisés pour la fabrication du circuit de gaz du régulateur thermique de débit massique ou des équipements auxiliaires.
Si cette méthode est employée pour la préparation de mélanges de gaz pour étalonnage, la performance optimale est la suivante: l'incertitude de mesure relative élargie U, obtenue en multipliant l'incertitude-type par un facteur d'élargissement k = 2, n'est pas supérieure à 2 %.
Lorsque des prémélanges gazeux sont utilisés à la place de gaz purs, il est possible d'obtenir des fractions molaires inférieures à 10−6. Le mesurage du débit massique n'étant alors pas suffisamment précis, le régulateur de débit doit faire l'objet d'un étalonnage indépendant.
Cette méthode a pour principal mérite de permettre la préparation en continu d'un mélange de gaz pour étalonnage en grande quantité ainsi que de rendre la préparation de mélanges à plusieurs constituants aussi simple que celle de mélanges ne comptant que deux constituants, à condition d'utiliser le nombre approprié de régulateurs thermiques de débit massique.
NOTE       Des systèmes permettant le mélange des gaz à partir de régulateurs thermiques de débit massique existent dans le commerce, certains offrant la possibilité d'informatiser et d'automatiser les commandes.

Analiza plinov - Priprava kalibracijskih plinskih zmesi z uporabo dinamičnih metod - 7. del: Termični regulatorji masnega pretoka (ISO 6145-7:2018)

ISO 6145 je skupina dokumentov, ki obravnava različne dinamične metode, ki se uporabljajo za pripravo kalibracijskih plinskih zmesi. Ta dokument določa metodo za kontinuirano pripravo kalibracijskih plinskih zmesi, od nominalno čistih plinov ali plinskih zmesi z uporabo termičnih regulatorjev masnega pretoka. Metoda se uporablja pri pripravi zmesi nereaktivnih primerkov, ki ne reagirajo z nobenim materialom konstrukcije poti pretoka v termičnem regulatorju masnega pretoka ali pomožni opremi.
Če se ta metoda uporablja pri pripravi kalibracijskih plinskih zmesi, je optimalna zmogljivost naslednja: relativna razširjena merilna negotovost U, pridobljena z zmnožkom standardne negotovosti in faktorja pokritja k = 2, ni večja od 2 %.
Če so namesto čistih plinov uporabljeni predmešani plini, je mogoče pridobiti molske frakcije pod 10−6. Meritev masnega pretoka ni absolutna in regulator pretoka potrebuje neodvisno umerjanje. Prednost metode je, da omogoča stalno pripravo večje količine kalibracijskih plinskih zmesi in pripravo večkomponentnih zmesi na enak način kot pri dvokomponentnih zmeseh, če je uporabljeno ustrezno število termičnih regulatorjev masnega pretoka.
OPOMBA: Sistemi za mešanje plinov, ki temeljijo na termičnih regulatorjih masnega pretoka, ter nekateri, ki vključujejo možnost računalniške obdelave podatkov in samodejnega nadzora, so komercialno dostopni.

General Information

• Status: Published
• Publication Date: 18-Dec-2018
• ICS: 71.040.40 - Chemical analysis
• Technical Committee: CEN/TC 238 - Test gases, test pressures and categories of appliances
• Drafting Committee: CEN/TC 238 - Test gases, test pressures and categories of appliances
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 19-Dec-2018
• Completion Date: 19-Dec-2018
• Ref Project: SIST EN ISO 6145-7:2019 - Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2018)

Relations

• Replaces: EN ISO 6145-7:2010 - Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2009)
• Effective Date: 26-Dec-2018

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2019
1DGRPHãþD
SIST EN ISO 6145-7:2011
$QDOL]DSOLQRY3ULSUDYDNDOLEUDFLMVNLKSOLQVNLK]PHVL]XSRUDERGLQDPLþQLKPHWRG
GHO7HUPLþQLUHJXODWRUMLPDVQHJDSUHWRND,62
Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 7:
Thermal mass-flow controllers (ISO 6145-7:2018)
Gasanalyse - Herstellung von Kalibriergasgemischen mit Hilfe von dynamisch-
volumetrischen Verfahren - Teil 7: Thermische Massendurchflussregler (ISO 6145-
7:2018)
Analyse des gaz - Préparation des mélanges de gaz pour étalonnage à l'aide de
méthodes dynamiques - Partie 7: Régulateurs thermiques de débit massique (ISO 6145-
7:2018)
Ta slovenski standard je istoveten z: EN ISO 6145-7:2018
ICS:
71.040.40 Kemijska analiza Chemical analysis
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 6145-7
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 71.040.40 Supersedes EN ISO 6145-7:2010
English Version
Gas analysis - Preparation of calibration gas mixtures
using dynamic methods - Part 7: Thermal mass-flow
controllers (ISO 6145-7:2018)
Analyse des gaz - Préparation des mélanges de gaz Gasanalyse - Herstellung von Kalibriergasgemischen
pour étalonnage à l'aide de méthodes dynamiques - mit Hilfe von dynamisch-volumetrischen Verfahren -
Partie 7: Régulateurs thermiques de débit massique Teil 7: Thermische Massendurchflussregler (ISO 6145-
(ISO 6145-7:2018) 7:2018)
This European Standard was approved by CEN on 16 October 2018.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
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 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6145-7:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 6145-7:2018) has been prepared by Technical Committee ISO/TC 158 "Analysis
of gases" in collaboration with CCMC.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2019, and conflicting national standards shall be
withdrawn at the latest by June 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 6145-7:2010.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 6145-7:2018 has been approved by CEN as EN ISO 6145-7:2018 without any
modification.
INTERNATIONAL ISO
STANDARD 6145-7
Third edition
2018-12
Gas analysis — Preparation of
calibration gas mixtures using
dynamic methods —
Part 7:
Thermal mass-flow controllers
Analyse des gaz — Préparation des mélanges de gaz pour étalonnage
à l'aide de méthodes dynamiques —
Partie 7: Régulateurs thermiques de débit massique
Reference number
ISO 6145-7:2018(E)
©
ISO 2018
ISO 6145-7:2018(E)
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 6145-7:2018(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
6 Set-up . 2
6.1 General . 2
6.2 Thermal mass-flow controller using a constant current supply . 3
6.3 Thermal mass-flow controller under constant temperature control . 3
7 Preparation of gas mixtures . 4
7.1 Description of the experimental procedure . . 4
7.2 Range of validity . 6
7.3 Operating conditions . 6
8 Calculations. 7
8.1 Volume fraction . 7
8.2 Sources of uncertainty . 7
8.3 Uncertainty of measurement . 8
Annex A (informative) Pre-mixed gases for the preparation of mixtures of high dilution .9
Annex B (informative) Practical hints .10
Annex C (informative) Calculation of uncertainties .12
Bibliography .14
ISO 6145-7:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 158, Analysis of gases.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
This third edition cancels and replaces the second edition (ISO 6145-7:2009), which has been technically
revised. The main changes compared to the previous edition are as follows:
— correction of some errors in the formulae in Annexes A and C;
— minor editorial corrections.
A list of all parts in the ISO 6145 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 6145-7:2018(E)
Gas analysis — Preparation of calibration gas mixtures
using dynamic methods —
Part 7:
Thermal mass-flow controllers
1 Scope
ISO 6145 is a series of documents dealing with various dynamic methods used for the preparation of
calibration gas mixtures. This document specifies a method for continuous preparation of calibration
gas mixtures, from nominally pure gases or gas mixtures by use of thermal mass-flow controllers. The
method is applicable to preparation of mixtures of non-reacting species, i.e. those which do not react
with any material of construction of the flow path in the thermal mass-flow controller or the ancillary
equipment.
If this method is employed for preparation of calibration gas mixtures the optimum performance is
as follows: the relative expanded measurement uncertainty U, obtained by multiplying the standard
uncertainty by a coverage factor k = 2, is not greater than 2 %.
−6
If pre-mixed gases are used instead of pure gases, mole fractions below 10 can be obtained. The
measurement of mass flow is not absolute and the flow controller requires independent calibration.
The merits of the method are that a large quantity of the calibration gas mixture can be prepared on a
continuous basis and that multi-component mixtures can be prepared as readily as binary mixtures if
the appropriate number of thermal mass-flow controllers is utilized
...