Bsi bs en 27842 1991 (1999) iso 7842 1988

00257495 PDF BRITISH STANDARD BS EN 27842 1991 ISO 7842 1988 Methods for Determination of discharge capacity of automatic steam traps The European Standard EN 27842 1991 has the status of a British St[.]

BRITISH STANDARD BS EN

27842:1991 ISO 7842:1988

Methods for

Determination of

discharge capacity of

automatic steam traps

The European Standard EN 27842:1991 has the status of a

British Standard

BS EN 27842:1991

This British Standard was

published under the authority

of the Standards Board and

comes into effect on

29 November 1991

© BSI 11-1999

The following BSI references

relate to the work on this

standard:

Committee reference PSE/7

Draft for comment 85/72012 DC

ISBN 0 580 20222 4

Cooperating organizations

The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries

Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y

France Association française de normalisation Germany Deutsches Institut für Normung e.V

Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland

Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portuguès da Qualidade Spain Asociación Española de Normalización y Certificación Sweden Standardiseringskommissionen i Sverige

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

Amd No Date Comments

BS EN 27842:1991

Contents

Page Cooperating organizations Inside front cover

National appendix NA (informative) 14 National appendix NB (informative) Inside back cover

BS EN 27842:1991

National foreword

This British Standard has been prepared under the direction of the Piping Systems Components Standards Policy Committee It is the English language

version of EN 27842:1991 “Automatic steam traps — Determination of discharge

capacity — Test methods” published by the European Committee for

Standardization (CEN) It supersedes BS 6028:1990 which is withdrawn

EN 27842:1991 is identical with ISO 7842:1988 published by the International Organization for Standardization (ISO)

A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application

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

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 14, an inside back cover and a back cover

This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 27842:1991

October 1991

UDC 621.646.9.057:621.186.1:620.1:532.57

Descriptors: Industrial valves, traps: drainage, water vapour, steam, tests, flow measurements

English version

Automatic steam traps — Determination of discharge

capacity — Test methods

(ISO 7842:1988)

Purgeurs automatiques de vapeur d’eau —

Détermination du débit — Méthodes d’essai

(ISO 7842:1988)

Kondensatableiter — Bestimmung des Durchflusses — Prüfverfahren

(ISO 7842:1988)

This European Standard was approved by CEN on 30 September 1991 and is

identical to the ISO standard as referred to

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 Central Secretariat 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

Central Secretariat has the same status as the official versions

CEN members are the national standards bodies of Austria, Belgium,

Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and

United Kingdom

CEN

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

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© CEN 1991 Copyright reserved to all CEN members

Ref No EN 27842:1991 E

EN 27842:1991

© BSI 11-1999 2

Foreword

On the proposal of the Technical Committee

CEN/TC 69 “Industrial Valves” CEN BT decided by

resolution C67/1990 to submit the International

Standard

ISO 7842:1988: Automatic steam traps —

Determination of capacity — Test methods to

Formal Vote

This European Standard was adopted by CEN

on 5 August 1991

According to the Common CEN/CENELEC Rules,

the following countries are bound to implement this

European Standard:

Austria, Belgium, Denmark, Finland, France,

Germany, Greece, Iceland, Ireland, Italy,

Luxembourg, Netherlands, Norway, Portugal,

Spain, Sweden, Switzerland and United Kingdom

Endorsement

The text of the International Standard

ISO 7482:1988 was approved by CEN as a European

Standard without any modifications

Contents

Page

1 Scope and field of application 3

6 Reporting of results — Test

Figure 1 — Test arrangement for

Figure 2 — Test arrangement for test method B — Continuous and

Figure 3 — Maximum submergence on steam trap versus test pressure 10

EN 27842:1991

1 Scope and field of application

This International Standard specifies two test methods to determine the discharge capacity of automatic steam traps to ISO 6552

2 References

ISO 651, Solid-stem calorimeter thermometers

ISO 652, Enclosed-scale calorimeter thermometers

ISO 653, Long solid-stem thermometers for precision use

ISO 654, Short solid-stem thermometers for precision use

ISO 4185, Measurement of liquid flow in closed conduits — Weighing method

ISO 5167, Measurement of fluid flow by means of orifice plates, nozzles and Venturi tubes inserted in

circular cross-section conduits running full

ISO 5168, Measurement of fluid flow — Estimation of uncertainty of a flow-rate measurement

ISO 6552, Automatic steam traps — Definition of technical terms

3 Test arrangements

The test arrangements for condensate capacity determination are shown in Figure 1 and Figure 2

All piping and equipment shall be insulated to a value of

to reduce thermal losses to a minimum

The instruments used for the measurements shall comply with International Standards, if such standards exist, e.g

— ISO 651, ISO 652, ISO 653 and ISO 654 for temperature measurements;

— ISO 4185, ISO 5167 and ISO 5168 for flow measurements

The condensate removal device shall not be modified in any way from its commercial form

4 Test method A

NOTE 1 The diameter of the pipework from the accumulator to the condensate removal device shall be the same as, or greater than, the diameter of the pipework to the inlet

connection on the device.

NOTE 2 The distance L1 shall not exceed 10 internal pipe diameters.

NOTE 3 The distance L2 shall be not less than 10 or more than 20 internal pipe diameters.

NOTE 4 The distance Z shall be measured vertically from the centre of the inlet connection of the condensate removal device.

Figure 1 — Test arrangement for test method A

EN 27842:1991

4.1 Procedure

NOTE Test method A is applicable only to continuous discharge measurement.

Start with all valves closed

4.1.1 Warm up the system by gradually opening valves 1, 2, 3, 4 and 5

4.1.2 Adjust valves 1, 2 and 3 with valve 4 wide open and valve 5 closed to bring the system into

equilibrium Equilibrium is defined as a steady water level in the accumulator with the vent valve 3 partially open and a difference of 3 °C or less showing on the temperature differential indicator

4.1.3 Observe and record the following data as appropriate depending on the method of condensate determination:

— p1 = steam supply pressure, in bars1);

— p2 = accumulator steam pressure, in bars;

— p3 = trap inlet pressure, in bars;

— p4 = trap outlet pressure, in bars;

— Ú1 = steam supply temperature, in degrees Celsius;

— Ú2 = water supply temperature, in degrees Celsius;

— %Ú = temperature differential (subcooling) between steam in the accumulator and fluid entering the trap, in degrees Celsius;

— X = steam supply quality, in per cent;

— Z = accumulator water level, in metres;

— %t = time interval, in hours, minutes or seconds;

— q m1 = water supply flow-rate, in kilograms per hour;

— q m2 = steam supply flow-rate, in kilograms per hour;

— mc1 = mass of condensate and tank at start, in kilograms;

— mc2 = mass of condensate and tank at end, in kilograms

It is emphasized that Figure 1 shows two alternative test arrangements for condensate measurement and that the choice is left to the test laboratory

4.1.4 Record the data specified in 4.1.3 at 5 min intervals for a minimum total of five sets of observations 4.1.5 During the test period observations as appropriate shall not exceed the following limits:

a) the difference between the maximum and minimum tank level shall not exceed 50 mm;

b) the maximum value of the tank level shall not exceed 450 mm at any time during the test;

c) the maximum temperature differential (%Ú) shall not exceed 3 °C during the test;

d) no individual trap inlet pressure (p3) observation shall vary by more than 1 % of the average of all observations;

e) the calculated vent steam flow-rate (q m6) shall not exceed a maximum value equal to an exit velocity

of 0,31 m/s in the tank

4.1.6 Repeat the operations specified in 4.1.1 to 4.1.5 as necessary to produce three sets of observations

which result in three calculated capacity ratings, none of which varies from the average by more than 10 %

1) 1 bar = 10 5 Pa

EN 27842:1991

4.2 Flow calculations

or

where

q mf is the discharge flow, in kilograms per hour;

q m1 is the water flow, in kilograms per hour;

q m3 is the steam flow to heat water supply (q m1), in kilograms per hour;

q m4 is the flash steam flow in the accumulator, in kilograms per hour;

q m8 is the accumulator storage rate, in kilograms per hour;

mc1 and mc2 are as given in 4.1.3;

h1 is the specific enthalpy of the supply water, in kilojoules per kilogram;

h2 is the specific enthalpy of the supply steam, in kilojoules per kilogram;

h3 is the specific enthalpy of saturated water at the supply pressure, in kilojoules per kilogram;

h4 is the specific enthalpy of saturated steam in the accumulator, in kilojoules per kilogram;

h5 is the specific enthalpy of saturated water in the accumulator, in kilojoules per kilogram;

v1 is the specific volume of saturated steam in the accumulator, in cubic metres per kilogram;

v2 is the specific volume of saturated water in the accumulator, in cubic metres per kilogram;

%t is time interval, in seconds;

D is the inside diameter of the accumulator, in metres;

Z1 is the initial accumulator tank level, in metres;

Z2 is the final accumulator tank level, in metres

EN 27842:1991

4.3 Data sheet

EN 27842:1991

5 Test method B

NOTE 1 The piping from the accumulator to the test device shall be of the same diameter as the inlet connection on the test device This inlet to the piping from the accumulator

shall be well-rounded.

NOTE 2 The distance between the sensors and the test device shall not exceed 20 internal pipe diameters.

NOTE 3 The distance Z shall be measured vertically from the centre of the inlet pipe connection of the test device and shall not exceed the distance shown in Figure 3.

NOTE 4 The diagram indicates the use of a steam injector for heating the water in the accumulator It could equally be achieved by the use of a steam circulating coil inside the

accumulator or any other means.

Figure 2 — Test arrangement for test method B — Continuous and intermittent flow

EN 27842:1991

5.1 Procedure

Start with all valves closed

5.1.1 Open valves 1 and 2 and fill the accumulator tank to the desired level Close valve 1

5.1.2 Open valve 3 and heat the water in the accumulator tank to the desired temperature Throttle valve 2

as required to obtain water temperatures above 100 °C Leave valve 2 open slightly while venting steam to purge air from the space above the water Close valves 2 and 3 and open valve 4

5.1.3 Open valves 5 and 6 to heat the test pipe and condensate removal device Monitor and adjust the system to produce the desired pressure at the test condensate removal device

5.1.4 When thermal equilibrium is reached, begin the test A circulation device may be necessary to ensure uniform temperature within the tank Do not take data until the tank level complies with that shown

in Figure 3

5.1.5 Observe and record as appropriate the following data:

a) elapsed time, in hours, minutes or seconds;

b) ambient temperature Úa, in degrees Celsius;

c) barometric pressure pa, in bars;

d) steam pressure and temperature ps and Ús, in bars and degrees Celsius;

e) initial and final values of the following:

1) temperature differential Ús – Úc, in degrees Celsius,

2) inlet pressure p1, in bars;

3) back pressure, p2, in bars;

f) one of the following:

1) accumulator tank levels Z1 and Z2, in metres,

2) mass of condensate plus weight of tank at start and finish mc, in kilograms

5.1.6 Repeat the operations specified in 5.1.1 to 5.1.5 as necessary to produce three sets of observations

which result in three calculated capacity ratings, none of which varies from the average by more than 10 %

Figure 3 — Maximum submergence on steam trap versus test pressure

EN 27842:1991

5.2 Flow calculations

where

q mf is the discharge flow, in kilograms per hour;

D is the inside diameter of the accumulator, in metres;

%t is the time interval, in seconds;

vf is the specific volume of water in the accumulator, in cubic metres per kilogram;

or

where

mc1 is the mass of condensate plus weigh tank at start, in kilograms;

mc2 is the mass of condensate plus weigh tank at end, in kilograms

5.3 Data sheet

EN 27842:1991

EN 27842:1991

6 Reporting of results — Test method A or B

Test results may be reported only if the following additional data are reported:

a) trap inlet pressure;

b) trap outlet pressure;

c) subcooling, %Ú

A minimum of five tests shall be used to plot any graph The extrapolation of any graph outside of the pressure range covered by the tests shall be clearly marked and the maximum subcooling (%Úmax) and minimum outlet pressure of the tests shall be noted on the graph

7 Bibliography

ISO 6704, Automatic steam traps — Classification

ISO 6948, Automatic steam traps — Production and performance characteristic tests

BS EN 27842:1991

National appendix NA (informative)

The United Kingdom participation in the preparation of this European Standard was entrusted by the Piping Systems Components Standards Policy Committee (PSE/-) to Technical Committee PSE/7, upon which the following bodies were represented:

Amalgamated Engineering Union

Association of Bronze and Brass Founders

Association of Building Component Manufacturers

British Chemical Engineering Contractors’ Association

British Foundry Association

British Gas plc

British Maritime Technology

British Plumbing Fittings Manufacturers’ Association

British Valve and Actuator Manufacturers’ Association

Chartered Institution of Building Services Engineers

Copper Development Association

Department of the Environment (Property Services Agency)

Electricity Industry in United Kingdom

Energy Industries Council

Engineering Equipment and Materials Users’ Association

Fire Extinguishing Trades Association

GAMBICA (BEAMA Ltd.)

Health and Safety Executive

Institute of British Foundrymen

Institution of Chemical Engineers

Institution of Mechanical Engineers

Institution of Water and Environmental Management

Liquefied Petroleum Gas Industry Technical Association (UK)

Pipeline Industries Guild

Society of British Gas Industries

Society of British Water Industries

Water Companies Association

Water Services Association of England and Wales

West Midlands CBI