SIST EN 12178:2004
(Main)Refrigerating systems and heat pumps - Liquid level indicating devices - Requirements, testing and marking
Refrigerating systems and heat pumps - Liquid level indicating devices - Requirements, testing and marking
This European standard describes requirements and tests for liquid level indicating devices used in refrigerating systems and heat pumps. It applies to devices connected to refrigerant vessels (e.g. on high-pressure liquid receivers, intercoolers and low-pressure separators) and to devices connected to other parts of a refrigerating system (e.g. oil-level sight glasses on a compressor).
Kälteanlagen und Wärmepumpen - Flüssigkeitsstandanzeiger - Anforderungen, Prüfung und Kennzeichnung
Diese Europäische Norm beschreibt Anforderungen und Prüfungen für Flüssigkeitsstandanzeiger, die in Kälteanlagen und Wärmepumpen eingesetzt werden. Sie gilt für Standanzeiger an Kältemittelbehältern (z.B. Hochdruck-Flüssigkeitssammler, Zwischenkühler und Niederdruck-Abscheider) und an anderen Teilen einer Kälteanlage (z.B. Ölschaugläser an einem Verdichter).ll -t ^head -10
Systemes de réfrigération et pompes a chaleur - Indicateurs de liquide - Exigences, essais et marquage
La présente Norme européenne spécifie les exigences de sécurité, les coefficients de sécurité, les méthodes d'essai, les pressions d'essai utilisées ainsi que le marquage des appareils indicateurs de niveau de liquide, ci-apres désignés par « indicateurs de niveau », destinés a etre utilisés dans les systemes de réfrigération et les pompes a chaleur.
Elle s'applique aux appareils reliés a des récipients de fluide frigorigene (par exemple réservoirs de liquide haute pression, sous-refroidisseurs et séparateurs basse pression) et aux appareils reliés a d'autres éléments d'un systeme de réfrigération (par exemple des voyants de niveau d'huile sur un compresseur).
La présente Norme européenne s'applique aux types d'indicateurs de niveau a lecture directe et indirecte (par exemple voyants, tubes de givrage) y compris les indicateurs électriques et pneumatiques.
La présente Norme européenne décrit la procédure a suivre lors de la conception (par calcul ou par une méthode expérimentale de conception) des éléments d'indicateur de niveau soumis a une pression, ainsi que les criteres a appliquer lors de la sélection des matériaux.
La présente Norme européenne s'applique a la conception des indicateurs de niveau eu égard au confinement de la pression et décrit les méthodes permettant de prendre en compte en toute sécurité des valeurs de résilience faibles a basse température.
Elle fournit également des lignes directrices sur certains aspects de la mise en oeuvre et de l'installation.
Hladilni sistemi in toplotne črpalke - Naprave, ki označujejo nivo tekočine – Zahteve, preskušanje in označevanje
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Refrigerating systems and heat pumps - Liquid level indicating devices - Requirements, testing and markingSystemes de réfrigération et pompes a chaleur - Indicateurs de liquide - Exigences, essais et marquageKälteanlagen und Wärmepumpen - Flüssigkeitsstandanzeiger - Anforderungen, Prüfung und KennzeichnungTa slovenski standard je istoveten z:EN 12178:2003SIST EN 12178:2004en27.20027.080ICS:SLOVENSKI
STANDARDSIST EN 12178:200401-september-2004
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12178December 2003ICS 27.080; 27.200English versionRefrigerating systems and heat pumps - Liquid level indicatingdevices - Requirements, testing and markingSystèmes de réfrigération et pompes à chaleur -Indicateurs de liquide - Exigences, essais et marquageKälteanlagen und Wärmepumpen -Flüssigkeitsstandanzeiger - Anforderungen, Prüfung undKennzeichnungThis European Standard was approved by CEN on 3 November 2003.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2003 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12178:2003 E
EN 12178:2003 (E)2ContentspageForeword.31Scope.42Normative references.43Terms and definitions.54List of Symbols.65General requirements.66Materials.77Design.88Fitting requirements.109Testing.1010Application.1011Marking and additional information.1112Documentation.11Annex ZA (informative)
Relationship between this European Standard and the Essential Requirementsof EU Directive 97/23/EC.13Bibliography.14
EN 12178:2003 (E)3ForewordThis document (EN 12178:2003) has been prepared by CEN/TC 182, "Refrigerating systems, safety andenvironmental requirements", the secretariat of which is held by DIN.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by June 2004, and conflicting national standards shall be withdrawn at the latest byJune 2004.This document has been prepared under a mandate given to CEN by the European Commission and the EuropeanFree 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.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
EN 12178:2003 (E)41 ScopeThis European Standard specifies safety requirements, safety factors, test methods, test pressures and marking ofliquid level indicating devices, referred to throughout this standard as "level indicators", for use in refrigeratingsystems and heat pumps.It applies to devices connected to refrigerant vessels (e.g. on high-pressure liquid receivers, intercoolers and low-pressure separators) and to devices connected to other parts of a refrigerating system (e.g. oil-level sight glasseson a compressor).This European Standard applies to those types of level indicators that are direct and indirect reading devices (e.g.sight glasses, frosting tubes), and includes electrical and pneumatic indicators.This European Standard describes the procedure to be followed when designing (by calculation or by anexperimental design method) level indicator parts subjected to pressure as well as the criteria to be used for theselection of materials.This European Standard applies to the design of level indicators with respect to pressure containment anddescribes methods by which the reduced impact values at lower temperatures may be taken into account in a safemanner.It also gives guidance on some aspects of application and installation.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 378-1, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 1: Basicrequirements, definitions, classification and selection criteria.EN 378-2, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 2: Design,construction, testing, marking and documentation.EN 378-4, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 4: Operation,maintenance, repair and recovery.prEN 764-1,
Pressure equipment — Terminology
— Part 1: Pressure, temperature, volume, nominal size.EN 12284:2003, Refrigerating systems and heat pumps — Valves — Requirements, testing and marking.EN 60529, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989).EN ISO 6708:1995, Pipework components — Definition and selection of DN [nominal size] (ISO 6708:1995).ISO 7268, Pipe components - Definition of nominal pressure.
EN 12178:2003 (E)53 Terms and definitionsFor the purposes of this European Standard, the terms and definitions given in EN 378-1 and prEN 764-1 and thefollowing
apply.3.1min t0 100lowest temperature at which pressurized parts can be used at a load of up to 100 % of the allowable design stressat 20 °C, taking the safety factors according to Table A.2 of EN 12284:2003 into account3.2min t0 75lowest temperature at which pressurized parts can be used, if its load amounts to 75 % maximum of the allowabledesign stress at 20 °C, taking the safety factors according to Table A.2 of EN 12284:2003 into account3.3min t0 25lowest temperature at which pressurized parts can be used, if their load amounts to 25 % maximum of theallowable design stress at 20 °C, taking the safety factors according to Table A.2 of EN 12284:2003 into account3.4self-closing ballsself-closing shut-off arrangementNOTEThe arrangement comprises balls positioned in the connecting channel close to the sight glass in such a mannerthat the balls will not be affected at low flow rates. At high flow rates the balls will be carried forward with the flow and block theconnections to the sight glass.3.5reflex glassglasses having prismatic flutes on the inside, which will break up the incoming lightNOTEThe liquid zone will absorb the light and will correspondingly appear dark. The gas/vapour zone will reflect the lightand will correspondingly appear bright.3.6direct reading level indicatorlevel indicator where it is possible to see the liquid level3.7indirect reading level indicatorlevel indicator where the liquid level is not visibleNOTEThe level is indicated by auxiliary means; electrically, magnetically or by observing the frost on a tube.3.8self-contained unitlevel indicator which is assembled and tested by the manufacturer3.9add-on unitlevel indicator delivered in parts from the manufacturer for mounting directly onto the system and which can only betested after assembly and connection on site3.10level indicator with magnetically operated indicationdevice which transfers the measured value at any particular moment to an indicating device by means of a floatwith a built-in permanent magnet system3.11sight glassdirect reading level indicator consisting of a glass plate and holder to enable viewing of the liquid surface
EN 12178:2003 (E)6NOTEThe shape of the glass plate can be either circular or oblong. The glass can be smooth or provided with flutes tobreak up incoming light which will make the liquid-filled part darker than the vapour-filled part. A sight glass can be a self-contained or add-on unit.3.12frosting tubedevice, the principle of which is based on the frosting of the humidity of the surrounding air, and which consists of acorrosion protected tube arranged vertically outside the vessel and connected to the vessel at top and bottom. It isespecially suitable for refrigerant temperatures below – 3° C and ambient temperature above freezing point. Thetop level of the frosting on the tube will indicate the liquid level in the vessel3.13auxiliary powered level indicatordevice which operates electrically or pneumatically to indicate the level by means such as the following:a) differential pressure transducer;b) capacitative transducer;c) inductive transducer;d) ultrasonic transducer;e) displacement principle with a displacement float.3.14operating rangetemperature and pressure conditions at which the liquid level can be safely operated3.15nominal size [DN]alpha-numeric designation of size for components of a pipework system [see EN ISO 6708:1995]3.16Nominal pressure (PN)value of a pressure in the range of the maximum allowable pressure for planning a plant or a component [seeISO 7268]4 List of SymbolsFor symbols see EN 12284:2003, clause 4 (Table 1).5 General requirements5.1 Installation and operationLevel indicators shall be designed for installation and operation in accordance with EN 378-1, EN 378-2 andEN 378-4.5.2 Components under pressureAll parts of the level indicator shall be designed and manufactured to remain leakproof and withstand the pressureswhich may occur during operation, standstill and transportation, taking into account the thermal, physical andchemical stresses t
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