1、BRITISH STANDARD BSISOAutomatic steam traps UDC621.186.6:001.4 Incorporating corrigendum July 2009 Definition of technical terms 6552:1980National foreword This British Standard is the UK implementation of ISO 6552:1980, incorporating corrigendum July 2009. It supersedes BS 6023:1981 (dual numbered
2、as BS 6023:1981 / ISO 6552:1980), which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee PSE/18, Industrial valves, steam traps, actuators and safety devices against excessive pressure, to Subcommittee PSE/18/1 Industrial valves, steam traps, actuators and s
3、afety devices against excessive pressure - Valves - Basic standards. A list of organizations represented on this subcommittee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct ap
4、plication. Compliance with a British Standard cannot confer immunity from legal obligations. BS ISO 6552:1980 This British Standard, having been prepared under the direction of the Mechanical Engineering Standards Committee, was published under the authority of the Executive Board and comes into eff
5、ect on 31 December 1980 The British Standards Institution 2012. Published by BSI Standards Limited 2012. Amendments/corrigenda issued since publication Date Comments 31 May 2012 Implementation of ISO corrigendum July 2009. The table in Subclause 2.3 has been amended, and the title has been aligned w
6、ith the ISO title. This corrigendum also renumbers BS 6023:1981 as BS ISO 6552:1980. ISBN 978 0 580 68660 31 0 Introduction The purpose of this International Standard is to establish precise definitions for technical terms and expressions which are commonly used to describe with a certain accuracy a
7、n automatic steam trap under operating conditions. This International Standard has to be considered in conjunction with every other International Standard using these terms and expressions to describe the technical characteristics or performances of an automatic steam trap. 1 Scope and field of appl
8、ication This International Standard gives the definitions of the major technical terms and expressions used to describe an automatic steam trap as far as dimension, pressure, temperature and flow rate are concerned, as well as their corresponding symbols and units. 2 Definition of technical terms 2.
9、1 dimension Term Symbol Unit Definition Nominal size DN Numerical designation of size which is common to all components in a piping system other than components designated by outside diameters. It is a convenient round number for reference purposes and is only loosely related to manufacturing dimens
10、ions. In any case, the nominal size DN cannot be subject to measurement and shall not be used for purposes of calculation. BS ISO 6552:19802 2.2 pressure Term Symbol Units a Definition Nominal pressure PN Numerical designation which is a convenient number for reference purposes. All equipment of the
11、 same nominal size (DN) designated by the same PN number shall have the same mating dimensions. The permissible working pressure depends upon the material, the design and the working temperature, and shall be selected from the pressure/temperature rating tables in this International Standard b . Max
12、imum allowable pressure PMA bar MPa Maximum pressure that the shell of the steam trap can withstand permanently at a given temperature. Maximum operating pressure PMO bar MPa Pressure for which a steam trap is rated by the manufacturer. This pressure is normally a function of the limitations related
13、 to the internal equipment of the steam trap. Operating pressure PO bar MPa Pressure measured at the inlet of the steam trap under operating conditions. Operating back pressure POB bar MPa Pressure measured at the outlet of the steam trap under operating conditions. Maximum operating back pressure P
14、MOB bar MPa Maximum permissible pressure at the outlet of the steam trap allowing correct functioning. Operating differential pressure %P bar MPa Difference between the operating pressure and the operating back pressure. Maximum differential pressure %PMX bar MPa Maximum difference between operating
15、 pressure and operating back pressure. Minimum differential pressure %PMN bar MPa Minimum difference between operating pressure and operating back pressure. Test pressure PT bar MPa Pressure applied to the steam trap under test. Maximum test pressure PTMX bar MPa Maximum test pressure of the steam t
16、rap including its internal mechanism. a 1bar=0,1MPa. b See the note in the national foreword. BS ISO 6552:19803 2.3 temperature 2.4 flow rate Term Symbol Unit Definition Basic temperature TB C Temperature taken into consideration in the determination of the dimensions of the steam trap. Maximum allo
17、wable temperature TMA C Maximum operating temperature TMO C Maximum temperature for which the operation of the steam trap is guaranteed. Operating temperature TO C Temperature measured at the inlet of the steam trap under operating conditions. Term Symbol Unit Definition Cold condensate capacity QC
18、kg/h Maximum mass of condensate that the steam trap can discharge in1h at a given differential pressure and a temperature of20 C, the trap being fully open. Hot condensate capacity QH kg/h Maximum mass of condensate that a steam trap can discharge in1h at a given differential pressure and temperatur
19、e. Maximum temperature to which the shell of the steam trap can be raised permanently at a given pressure . BS ISO 6552:1980BSI is the independent national body responsible for preparing British Standards and other standards-related publications, information and services. It presents the UK view on
20、standards in Europe and at the international level. BSI is incorporated by Royal Charter . British Standards and other standardization products are published by BSI Standards Limited. British Standards Institution (BSI) raising standards worldwide BSI 389 Chiswick High Road London W4 4AL UK Te l + 4
21、 4 ( 0 ) 2 0 8 9 9 6 9 0 0 1 Fax +44 (0)20 8996 7001 Revisions British Standards and PASs are periodically updated by amendment or revision. Users of British Standards and PASs should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality
22、 of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using British Standards would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Similary for PASs, please notify BSI Custome
23、r Services. Te l : + 4 4 ( 0 ) 2 0 8 9 9 6 9 0 0 1 F a x : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 1 BSI offers BSI Subscribing Members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of British Standards and PASs. Te l : + 4 4 ( 0 ) 2 0 8 9
24、9 6 7 6 6 9 F a x : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 1 Email: Buying standards Yo u m a y b u y P D F a n d h a rd c o p y v e r s i o n s o f s t a n d a rd s d i re c t l y u s i n g a credit card from the BSI Shop on the website In addition all orders for BSI, international and foreign standards p
25、ublications can be addressed to BSI Customer Services. Te l : + 4 4 ( 0 ) 2 0 8 9 9 6 9 0 0 1 F a x : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 1 Email: In response to orders for international standards, BSI will supply the British Standard implementation of the relevant international standard, unless otherwis
26、e requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Knowledge Centre. Te l : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 4 F a x : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 5 Email: BSI Subscribing Members are kept up to date with stand
27、ards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Te l : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 2 F a x : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 0 1 Email: Information regarding online access to British Sta
28、ndards and PASs via British Standards Online can be found at Further information about British Standards is available on the BSI website at Copyright All the data, software and documentation set out in all British Standards and other BSI publications are the property of and copyrighted by BSI, or
29、some person or entity that owns copyright in the information used (such as the international standardization bodies) has formally licensed such information to BSI for commercial publication and use. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, s
30、tored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. Details and advice can be obtained from the Copyright & Licensing Department. Te l : + 4 4 ( 0 ) 2 0 8 9 9 6 7 0 7 0 Email:
