1、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 StandardBSEN27842:1991 This British Standard was published under the authority ofthe Standards Board and comesinto
2、effect on 29November1991 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
3、 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 franaise de normalisation Germa
4、ny Deutsches Institut fr 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 Normali
5、satie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments
6、issued since publication Amd. No. Date CommentsBSEN27842:1991 BSI 11-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN 27842 3 National appendix NA (informative) 14 National appendix NB (informative) Inside back coverBSEN27842:1991 ii BSI 11
7、-1999 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 EN27842:1991 “Automatic steam traps Determination of discharge capacity Test methods” published by the European Commi
8、ttee for Standardization (CEN). It supersedes BS6028:1990 which is withdrawn. EN27842:1991 is identical with ISO7842:1988 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
9、 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 cove
10、r 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 EUROPENNE EUROPISCHE NORM EN 27842:1991 October 1991 UDC 621.646.9.057:621.186.1:620.1:532
11、.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 deau Dtermination du dbit Mthodes dessai (ISO 7842:1988) Kondensat
12、ableiter Bestimmung des Durchflusses Prfverfahren (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 t
13、his 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
14、(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, Denma
15、rk, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B
16、-1050 Brussels CEN 1991 Copyright reserved to all CEN members Ref. No. EN 27842:1991 EEN27842:1991 BSI 11-1999 2 Foreword On the proposal of the Technical Committee CEN/TC69 “Industrial Valves” CEN BT decided by resolution C67/1990 to submit the International Standard. ISO 7842:1988: Automatic steam
17、 traps Determination of capacity Test methods to Formal Vote. This European Standard was adopted by CEN on5August1991. According to the Common CEN/CENELEC Rules, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Icelan
18、d, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Endorsement The text of the International Standard ISO7482:1988 was approved by CEN as a European Standard without any modifications. Contents Page Foreword 2 1 Scope and field of application
19、 3 2 References 3 3 Test arrangements 3 4 Test method A 3 5 Test method B 8 6 Reporting of results Test method A or B 13 7 Bibliography 13 Figure 1 Test arrangement for test method A 4 Figure 2 Test arrangement for test method B Continuous and intermittent flow 9 Figure 3 Maximum submergence on stea
20、m trap versus test pressure 10EN27842:1991 BSI 11-1999 3 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-scal
21、e 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
22、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
23、 shown inFigure 1 andFigure 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, ISO652, ISO653 and ISO654 for temperature measure
24、ments; ISO 4185, ISO5167 and ISO5168 for flow measurements. The condensate removal device shall not be modified in any way from its commercial form. 4 Test method AEN 27842:1991 4 BSI 11-1999 NOTE 1The diameter of the pipework from the accumulator to the condensate removal device shall be the same a
25、s, or greater than, the diameter of the pipework to the inlet connection on the device. NOTE 2The distance L 1shall not exceed 10 internal pipe diameters. NOTE 3The distance L 2shall be not less than 10 or more than 20 internal pipe diameters. NOTE 4The distance Z shall be measured vertically from t
26、he centre of the inlet connection of the condensate removal device. Figure 1 Test arrangement for test method AEN27842:1991 BSI 11-1999 5 4.1 Procedure NOTETest method A is applicable only to continuous discharge measurement. Start with all valves closed. 4.1.1 Warm up the system by gradually openin
27、g valves1,2,3, 4 and5. 4.1.2 Adjust valves1,2 and3 with valve4 wide open and valve5 closed to bring the system into equilibrium. Equilibrium is defined as a steady water level in the accumulator with the vent valve3 partially open and a difference of3 C or less showing on the temperature differentia
28、l indicator. 4.1.3 Observe and record the following data as appropriate depending on the method of condensate determination: p 1= steam supply pressure, in bars 1) ; p 2= accumulator steam pressure, in bars; p 3= trap inlet pressure, in bars; p 4= trap outlet pressure, in bars; 1= steam supply tempe
29、rature, in degrees Celsius; 2= water supply temperature, in degrees Celsius; % = 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,
30、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; m c1= mass of condensate and tank at start, in kilograms; m c2= mass of condensate and tank at end, in kilograms. It is emphasized thatFigure 1 shows two alternativ
31、e test arrangements for condensate measurement and that the choice is left to the test laboratory. 4.1.4 Record the data specified in4.1.3 at5min 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
32、: a) the difference between the maximum and minimum tank level shall not exceed 50mm; b) the maximum value of the tank level shall not exceed450mm at any time during the test; c) the maximum temperature differential (% ) shall not exceed3 C during the test; d) no individual trap inlet pressure (p 3
33、) observation shall vary by more than1% 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 of0,31 m/s in the tank. 4.1.6 Repeat the operations specified in4.1.1 to4.1.5 as necessary to produce three sets of ob
34、servations which result in three calculated capacity ratings, none of which varies from the average by more than10%. 1) 1 bar = 10 5PaEN27842:1991 6 BSI 11-1999 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 th
35、e 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; m c1and m c2 are as given in4.1.3; h 1 is the specific enthalpy of the supply water, in kilojoules pe
36、r kilogram; h 2 is the specific enthalpy of the supply steam, in kilojoules per kilogram; h 3 is the specific enthalpy of saturated water at the supply pressure, in kilojoules per kilogram; h 4 is the specific enthalpy of saturated steam in the accumulator, in kilojoules per kilogram; h 5 is the spe
37、cific enthalpy of saturated water in the accumulator, in kilojoules per kilogram; v 1 is the specific volume of saturated steam in the accumulator, in cubic metres per kilogram; v 2 is the specific volume of saturated water in the accumulator, in cubic metres per kilogram; %t is time interval, in se
38、conds; D is the inside diameter of the accumulator, in metres; Z 1 is the initial accumulator tank level, in metres; Z 2 is the final accumulator tank level, in metres.EN27842:1991 BSI 11-1999 7 4.3 Data sheetEN27842:1991 8 BSI 11-1999 5 Test method BEN 27842:1991 BSI 11-1999 9 NOTE 1The piping from
39、 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 2The distance between the sensors and the test device shall not exceed20 internal pipe diameters. NOTE 3The distance
40、 Z shall be measured vertically from the centre of the inlet pipe connection of the test device and shall not exceed the distance shown inFigure 3. NOTE 4The 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 cir
41、culating coil inside the accumulator or any other means. Figure 2 Test arrangement for test method B Continuous and intermittent flowEN27842:1991 10 BSI 11-1999 5.1 Procedure Start with all valves closed. 5.1.1 Open valves1 and2 and fill the accumulator tank to the desired level. Close valve1. 5.1.2
42、 Open valve3 and heat the water in the accumulator tank to the desired temperature. Throttle valve2 as required to obtain water temperatures above100 C. Leave valve2 open slightly while venting steam to purge air from the space above the water. Close valves2 and3 and open valve4. 5.1.3 Open valves5
43、and6 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 tan
44、k. Do not take data until the tank level complies with that shown inFigure 3. 5.1.5 Observe and record as appropriate the following data: a) elapsed time, in hours, minutes or seconds; b) ambient temperature a , in degrees Celsius; c) barometric pressure p a , in bars; d) steam pressure and temperat
45、ure p sand s , in bars and degrees Celsius; e) initial and final values of the following: 1) temperature differential s c , in degrees Celsius, 2) inlet pressure p 1 , in bars; 3) back pressure, p 2 , in bars; f) one of the following: 1) accumulator tank levels Z 1and Z 2 , in metres, 2) mass of con
46、densate plus weight of tank at start and finish m c , in kilograms. 5.1.6 Repeat the operations specified in5.1.1 to5.1.5 as necessary to produce three sets of observations which result in three calculated capacity ratings, none of which varies from the average by more than10%. Figure 3 Maximum subm
47、ergence on steam trap versus test pressureEN27842:1991 BSI 11-1999 11 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; v f is the specific volume of water in the accumulator, in
48、 cubic metres per kilogram; or where m c1 is the mass of condensate plus weigh tank at start, in kilograms; m c2 is the mass of condensate plus weigh tank at end, in kilograms. 5.3 Data sheetEN27842:1991 12 BSI 11-1999EN27842:1991 BSI 11-1999 13 6 Reporting of results Test method A or B Test results
49、 may be reported only if the following additional data are reported: a) trap inlet pressure; b) trap outlet pressure; c) subcooling, % . 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 (% max ) and minimum outlet pressure of the tests shall be noted on the graph. 7 Bibliography ISO 6704, Automatic steam trap
