BS ISO 3567-2012 Vacuum gauges Calibration by direct comparison with a reference gauge《真空计 通过直接与标准真空计的比较进行校准》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 3567:2011V a c u u m g a u g e s Calibration by direct comparison with a r e f e r e n c e g a u g eBS ISO 3567:2011 BRITISH STANDARDNational forewordThis British Standard

2、 is the UK implementation of ISO 3567:2011. The UK participation in its preparation was entrusted to T e c h n i c a l Committee MCE/8/-/4, Vacuum technology.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include

3、 all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012 ISBN 978 0 580 74774 8 ICS 23.160 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the auth

4、ority of the Standards Policy and Strategy Committee on 31 January 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 3567:2011Vacuum gauges Calibration by direct comparison with a reference gaugeManomtres talonnage par comparaison directe avec un manomtre de rfrence ISO 2011

5、Reference numberISO 3567:2011(E)First edition2011-12-15ISO3567INTERNATIONAL STANDARDBS ISO 3567:2011ISO 3567:2011(E)COPYRIGHT PROTECTED DOCUMENT ISO 2011All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic

6、or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.i

7、so.orgPublished in Switzerlandii ISO 2011 All rights reservedBS ISO 3567:2011ISO 3567:2011(E) ISO 2011 All rights reserved iiiContents PageForeword ivIntroduction . v1 Scope 12 Normative references .13 Terms and definitions .14 Symbols and abbreviated terms .35 General principle .46 Requirements .46

8、.1 Design of calibration chamber .46.2 Plumbing of gauges to calibration chamber 56.3 Vacuum and gas inlet system 66.4 Calibration gas .66.5 Thermometers and ambient conditions 66.6 Reference gauge 77 Calibration .77.1 Procedure 77.2 Evaluation of measurements .97.3 Measurement uncertainty .98 Calib

9、ration certificate .10Annex A (informative) Example of possible calibration system set-up .11Annex B (informative) Problems in practice12Bibliography .14BS ISO 3567:2011ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member

10、 bodies). The work of preparing International Standards is normally carried out through ISO 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

11、 and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directive

12、s, Part 2.The main task of technical committees is to prepare International Standards. 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 ca

13、sting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 3567 was prepared by Technical Committee ISO/TC 112, Vacuum technology.This first edi

14、tion of ISO 3567 cancels and replaces ISO/TS 3567:2005, of which it constitutes a technical revision.ISO 3567:2011(E)iv ISO 2011 All rights reservedBS ISO 3567:2011IntroductionThe purpose of this International Standard is to establish the physical, technical and metrological conditions necessary for

15、 adequately disseminating the pressure scale in the vacuum regime by calibration with a reference gauge. It is assumed that the user will be familiar with the general procedures of vacuum generation and measurement in the vacuum ranges considered.ISO 3567:2011(E) ISO 2011 All rights reserved vBS ISO

16、 3567:2011BS ISO 3567:2011INTERNATIONAL STANDARD ISO 3567:2011(E)Vacuum gauges Calibration by direct comparison with a reference gauge1 ScopeThis International Standard specifies the physical, technical and metrological conditions to be fulfilled when calibrations of vacuum gauges are performed by d

17、irect comparison with a reference gauge. From the conditions described, the design of an apparatus that can perform vacuum gauge calibrations in an adequate manner can be deduced.The vacuum gauges to be calibrated can be of any kind. Many types of gauges consist of several parts. Typically, these ar

18、e: gauge head, cable, operational device and signal read out. This entire set is considered as the unit that has to be calibrated. Whereas, if only the gauge head (i.e. the part of the vacuum gauge directly exposed to the vacuum) is calibrated, all set-ups and conditions would have to be recorded su

19、ch that the user of the calibrated gauge head would be able to perform the measurements in the same manner as during the calibration.The reference gauge is either a calibrated gauge, traceable to a vacuum primary or national standard (normal case), with a calibration certificate according to ISO/IEC

20、 17025, or an absolute measuring instrument (rare case), traceable to the SI units and to which a measurement uncertainty can be attributed.This International Standard does not give guidance on how to treat special types of vacuum gauges, be they reference standards or units under calibration; it is

21、 intended that such guidance be given in other International Standards.The pressure range for calibrations treated in this International Standard depends on the realized design of the calibration apparatus and on the type of reference gauge. The range varies in its limits from 106Pa to 110 kPa.2 Nor

22、mative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO/IEC Guide 98-3, Uncertainty o

23、f measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)ISO/IEC 17025:2005, General requirements for the competence of testing and calibration laboratories3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1primary stan

24、dardmeasurement standard established using a primary reference measurement procedure SOURCE: ISO/IEC Guide 99:2007, 5.4, modified3.2national standardmeasurement standard recognized by national authority to serve in a state or economy as the basis for assigning quantity values to other measurement st

25、andards for the kind of quantity concernedSOURCE: ISO/IEC Guide 99:2007, 5.3 ISO 2011 All rights reserved 1BS ISO 3567:20113.3reference standardmeasurement standard designated for the calibration of other measurement standards for quantities of a given kind in a given organization or at a given loca

26、tionSOURCE: ISO/IEC Guide 99:2007, 5.6NOTE In this International Standard, it is synonymous with reference gauge.3.4vacuum gaugeinstrument for measuring gas or vapour pressure that is less than the prevailing atmospheric pressureSOURCE: ISO 3529-3:1981, 3.1.2NOTE 1 Some types of vacuum gauges common

27、ly in use do not measure a pressure directly, but measure some other physical quantity which, under specific conditions, is related to pressure.NOTE 2 For terms and definitions of the various vacuum gauges in use, see ISO 3529-3.3.5gauge headpart of the gauge which contains the pressure-sensitive el

28、ement and which is directly connected to the vacuum system NOTE A gauge head comprising its operational device is usually called a transmitter.SOURCE: ISO 3529-3:1981, 3.1.2.1, modified3.6operational devicepart of a vacuum gauge that operates the gauge head and/or delivers the signal related to pres

29、sure3.7unit under calibrationUUCvacuum gauge to be calibrated3.8entrance flangeflange by which the unit under calibration or the reference gauge is connected to the calibration chamber3.9calibration chambervacuum chamber that serves as a common vacuum medium for the reference gauge and unit under ca

30、libration3.10entrance mouthopening in the calibration chamber which leads to a unit under calibration, reference gauge or any other part of the calibration system3.11calibration gasgas species or mixture that is used to change the pressure in the calibration chamber3.12sorptiontaking up of a gas or

31、vapour by a solid or liquid3.13desorptionliberation of gases or vapours sorbed by a materialISO 3567:2011(E)2 ISO 2011 All rights reservedBS ISO 3567:20113.14outgassing raterate at which molecules and atoms desorb from a material exposed to a vacuum3.15total pressurepsum of pressures of all the comp

32、onents of a gaseous mixtureNOTE A vacuum is usually measured as the absolute pressure of gas prevalent in an enclosed chamber, expressed in pascals (Pa) or millibars (mbar): 1 mbar = 100 Pa; 1 bar = 0,1 MPa = 105Pa; 1 MPa = 1 N/mm2.3.16residual pressurelowest pressure that can be reached in the cali

33、bration chamber, typically after 24 h of pumpingNOTE The residual pressure depends, among others things, on the bake-out condition of the calibration chamber.3.17base pressurepressure in the calibration chamber that exists either before gas is admitted into the calibration chamber for calibration, o

34、r later, after the gas inlet valve has been turned off for some timeNOTE The base pressure can be higher than the residual pressure, but cannot be lower.4 Symbols and abbreviated termsD diameter of cylinder, expressed in millimetres (mm)e error of readingp total vacuum pressure, expressed in pascals

35、 (Pa) or millibar (mbar)p0base pressure, expressed in pascals (Pa) or millibar (mbar)pcalcalibration pressure, expressed in pascals (Pa) or millibar (mbar)pindindicated pressure, expressed in pascals (Pa) or millibar (mbar)presresidual pressure, expressed in pascals (Pa) or millibar (mbar)Qoutoutgas

36、sing rate, expressed in pascal litres per second (Pa L/s), pascal cubic metres per second (Pa m3/s) or millibar litres per second (mbar L/s)qv,effeffective volume flow rate of the pump e ffective litres per second (L/s) or cubic metres per second (m3/s) volume flow rate into pumpS sensitivity (coeff

37、icient) (Pa1)u standard uncertaintyU expanded uncertaintyCF correction factorUUC unit under calibrationISO 3567:2011(E) ISO 2011 All rights reserved 3BS ISO 3567:20115 General principleThe UUC is connected to the same calibration chamber as the reference gauge.Calibration of a vacuum gauge the UUC b

38、y comparison with a reference gauge is done by exposing the entrance flange of the UUC and that of the reference gauge to the same density and velocity distribution of calibration gas molecules. The same density and velocity distribution of these molecules means the same pressure at the two location

39、s, but not vice versa. Since there are many types of vacuum gauge that do not measure pressure b ut instead, for example, gas density or the impingement rate of gas molecules t he above requisite is both necessary and more stringent than only calling for equal pressures at the two entrance flanges.T

40、he gas density (pressure) in the calibration chamber can be varied and the gauge readings of the UUC compared with the pressures indicated by the reference gauge.From this general principle, the requirements (see Clause 6) for the design of the calibration apparatus are deduced.6 Requirements6.1 Des

41、ign of calibration chamberThe chamber shall be designed to ensure that the distribution of gas in the measuring volume is sufficiently uniform in space and stable in time.In addition, the material of the calibration chamber shall be chosen such that the residual pressure, pres, determined by the eff

42、ective pumping speed, qv,eff(effective volume flow rate into pump), and the total outgassing rate in the calibration chamber, Qout(absence of leaks), is low enough to perform the calibrations, as expressed by Formula (1) (see also 6.3):pQqresoutv,eff= (1)In detail, the calibration chamber shall be d

43、esigned and operated as follows. However, design criteria a) to e) may be disregarded when the minimum pressures to be realized in the vacuum chamber are larger than 100 Pa and only static pressures (see 7.1) are established. Independent of pressure, criteria b) to d) may be disregarded when only st

44、atic pressures are established.a) The calibration chamber shall have a volume of at least 20 times the total volume of all the gauges and associated pipe work connecting the chamber and the gauges (e.g. elbows shall be considered as part of the gauge volume).b) The shape of the calibration chamber (

45、see Figure 1) shall be cylinder-symmetrical to at least one axis. A sphere is ideal, but two symmetrical domes, each a part of a sphere and attached to one another, or cylinders, are equally possible. Where a cylinder is used, its overall length shall be within one and two times its diameter, and do

46、med ends are recommended.c) The centre of the cross-sectional area of the pumping outlet and the gas inlet (if applicable) shall lie on the same cylindrical axis of symmetry of the calibration chamber. The gas inlet may be positioned between the pump outlet and pump system (see 6.3), in which case t

47、here is no need to have the gas inlet on the axis of symmetry.d) All entrance mouths and their respective flanges to which either the UUCs or the reference gauges are to be connected shall be on a common equatorial plane, perpendicular to the cylindrical axis of symmetry chosen for the pumping outle

48、t.Where a cylinder is used, it is recommended that this equatorial plane separate the cylinder into two halves of equal length. Where a cylinder with a length of (3/2)D in relation to its diameter is used (suitable ISO 3567:2011(E)4 ISO 2011 All rights reservedBS ISO 3567:2011for pump speed measurem

49、ents), the gauges may be placed at one third of the length (D/2) above the bottom flange.e) Temperature differences between arbitrary points across the calibration chamber shall be less than 1 K. Points closer than 5 cm from the entrance mouth to a heated vacuum gauge head (e.g. ionization gauge) may be disregarded.f) The spatial see e) mean temperature of the calibration chamber shall be (23 3) C during calibration, while the mean temperature should not change by more than 1 K.If the design criteria a) to e)