ISO-10920-1997.pdf

INTERNATIONAL STANDARD IS0 10920 First edition 1997-03-I 5 Gas cylinders - 25E taper thread for connection of valves to gas cylinders - Specification Bouteilles ii gaz - Filetages coniques 25E pour le raccordement des robinets sur /es bouteiltes B gaz - Spkcifications This material is reproduced from IS0 documents under International Organization for Standardization (ISO) Copyright License number IHSIICCI1996. Not for resale. No part of these IS0 documents may be reproduced in any form, electronic retrieval system or otherwise, except as allowed in the copyright law of the country of use, or with the prior written consent of IS0 (Case postale 56,1211 Geneva 20, Switzerland, Fax +41 22 734 10 79), IHS or the IS0 Licensers members. Reference number IS0 10920:1997(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 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. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 10920 was prepared by Technical Committee ISO/TC 58, Gas cylinder, Subcommittee SC 2, Cylinder fittings. 0 IS0 1997 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Internet centraliso.ch x.400 c=ch; a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii -,-,- 0 IS0 Introduction This International Standard belongs to a series of standards specifying thread dimensions and gauge requirements. Cylinders intended to contain compressed, liquefied or dissolved gas under pressure are fitted with accessories (valves, straight or angle fittings) to allow release of and refilling with, gas. Hereinafter, the term “valve” will apply to such accessories. The connection between cylinder and valve is obtained by assembly of two taper threads, an external one on the valve stem and an internal one in the cylinder neck, both having the same nominal taper, pitch and thread profile. -,-,- INTERNATIONAL STANDARD 0 IS0 IS0 10920:1997(E) Gas cylinders - 25E taper thread for connection of valves to gas cylinders - Specification 1 Scope This International Standard specifies definitions, dimensions and tolerances of a taper screw thread of nominal diameter 25,8 mm (designated 25E), for the connection of valves to medical and industrial gas cylinders. This International Standard does not cover the connection requirements for - mechanical strength; - gas tightness; - capability of repeated assembly and dismounting operations. Inspection gauges are covered by IS0 11191 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 11 191: 1997, Gas cylinders - 25E taper thread for connection of valves to gas cylinders - inspection gauges. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 valve stem: Tapered end of the valve body, with a thread formed on the external surface of the truncated cone (see figure I). 3.2 cylinder neck thread: Tapered axial hole in the cylinder neck, with a thread formed on the internal surface of the truncated cone (see figure I). 1 IS0 10920:1997(E) Q IS0 3.3 major cone: Cone bounding the crests of the thread of the valve stem, or the roots of the cylinder neck thread. 3.4 minor cone: Cone bounding the roots of the thread of the valve stem, or the crests of the cylinder neck thread. 3.5 pitch cone: Cone passing coaxially and midway, between the major and minor cones. 3.6 reference plane A: Reference plane coincident with the small end face, of the threaded valve stem and corresponding to diameters dti, dl, and dl, (see figure I). 3.7 reference plane B: Reference plane, at a distance 1, from reference plane A and corresponding to diameter dzp (see figure 1). 3.8 reference plane F: Reference plane coincident with the entry section face of the cylinder neck thread and corresponding to diameter Dzp (see figure 1). 3.9 reference plane G: Reference plane, at a distance LJ from reference plane F and corresponding to diameters Dl, Dip and Dli (see figure I). 3.10 major diameter, dl - angle: 6” 52; - taper: 12 %. 4.3 Thread profile The thread profile shall be a standard Whitworth form, with a 55” angle. The form and thread height measurements are perpendicular to the cone surface (see figure 2). 4.4 Pitch, P The pitch shall be 1,814 mm (derived from 25,4 - mm) (see figure 2). 14 5 Thread end finish The thread of the valve stem may have a chamfer of 2 mm maximum, from plane A at the bottom part and a groove at the top (see figure I). The thread of the cylinder neck may have a chamfered opening of 2 mm maximum, from plane F (see figure 1). 6 Identification Valves and cylinders, threaded in accordance with this International Standard, shall be identified by the symbol “25E”. 5 -,-,- IS0 10920:1997(E) ICS 23.020.30 Descriptors: gas pressure vessels, gas cylinders, junctions, gas valves, taper threads, form specifications, dimensions, profiles, identification methods. Price based on 5 pages