BS ISO 21360-1-2012 Vacuum technology Standard methods for measuring vacuum-pump performance General description《真空技术 测量真空泵性能的标准方法 总则》.pdf

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1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 21360-1:2012Vacuum technology Standard methods formeasuring vacuum-pumpperformancePart 1: General descriptionBS ISO 21360-1:2012 BRITISH STANDARDNational forewordThis Brit

2、ish Standard is the UK implementation of ISO 21360-1:2012.It supersedes BS ISO 21360:2007 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee MCE/8/-/4, Vacuum technology.A list of organizations represented on this committee can beobtained on request to its

3、 secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 76006 8ICS 23.160Compliance with a British Standard cannot

4、 confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 May 2012.Amendments issued since publicationDate Text affectedBS ISO 21360-1:2012 ISO 2012Vacuum technology Standard methods for measuring vacuum-pump pe

5、rformancePart 1: General descriptionTechnique du vide Mthodes normalises pour mesurer les performances des pompes vide Partie 1: Description gnraleINTERNATIONAL STANDARDISO 21360-1First edition 2012-04-15Reference number ISO 21360-1:2012(E)BS ISO 21360-1:2012ISO 21360-1:2012(E)ii ISO 2012 All rights

6、 reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All 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 either ISO at the a

7、ddress 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.iso.orgPublished in SwitzerlandBS ISO 21360-1:2012ISO 21360-1:2012(E) ISO 2012 All rights reserved iiiConten

8、ts PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 14 Symbols and abbreviated terms . 35 Test methods 45.1 Volume flow rate (pumping speed) measurement by the throughput method . 45.2 Volume flow rate (pumping speed) measurement by the orifice method . 85.3

9、Volume flow rate (pumping speed) measurement by the pump-down method 135.4 Measurement of the base pressure 175.5 Measurement of the compression ratio and the critical backing pressure .18Annex A (informative) Mean free path of some important gases.22Annex B (informative) Measuring uncertainties .23

10、Bibliography .26BS ISO 21360-1:2012ISO 21360-1:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. E

11、ach 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. ISO collaborates closely with the Internati

12、onal Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standard

13、s 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.Attention is drawn to the possibility that some of the elements of this document may be the subject of

14、 patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 21360-1 was prepared by Technical Committee ISO/TC 112, Vacuum technology.This first edition of ISO 21360-1 cancels and replaces ISO 21360:2007, of which it constitutes a minor revision.ISO 21360 cons

15、ists of the following parts, under the general title Vacuum technology Standard methods for measuring vacuum-pump performance: Part 1: General description Part 2: Positive displacement vacuum pumpsiv ISO 2012 All rights reservedBS ISO 21360-1:2012ISO 21360-1:2012(E)IntroductionThis part of ISO 21360

16、 is a basic standard for measuring the performance data of vacuum pumps. The methods specified here are well known from existing national and International Standards. In developing this part of ISO 21360, the aim has been to provide a single document containing the measurements of performance data o

17、f vacuum pumps and to simplify the future development of specific vacuum pump standards.Specific vacuum pump standards will contain a suitable selection of measurement methods from this part of ISO 21360 in order to determine the performance data, limiting values and specific operational conditions

18、on the basis of the specific properties of the particular kind of pump. Whenever a discrepancy exists between this part of ISO 21360 and the specific standard, it is the specific standard which is valid. ISO 2012 All rights reserved vBS ISO 21360-1:2012BS ISO 21360-1:2012Vacuum technology Standard m

19、ethods for measuring vacuum-pump performance Part 1: General description1 ScopeThis part of ISO 21360 specifies three methods for measuring the volume flow rate and one method each for measuring the base pressure, the compression ratio, and the critical backing pressure of a vacuum pump.The first me

20、thod for measuring the volume flow rate (the throughput method) is the basic concept, in which a steady gas flow is injected into the pump while the inlet pressure is measured. In practice, the measurement of gas throughput may be complicated or inexact. For this reason, two other methods are specif

21、ied which avoid the direct measurement of throughput.The second method for measuring the volume flow rate (the orifice method) is used when there is very small throughput at very small inlet pressures (under a high or ultra-high vacuum). It is based on measuring the ratio of pressures in a two-chamb

22、er test dome in which the two chambers are separated by a wall with a circular orifice.The third method for measuring the volume flow rate (the pump-down method) is well suited for automated measurement. It is based on the evacuation of a large vessel. The volume flow rate is calculated from two pre

23、ssures, before and after a pumping interval, and from the volume of the test dome. Different effects, such as leak and desorption rates, gas cooling by nearly isentropic expansion during the pumping interval, and increasing flow resistance in the connection line between test dome and pump caused by

24、molecular flow at low pressures, influence the results of the pressure measurement and the resulting volume flow rate.The choice of the required measurement methods depends on the properties of the specific kinds of vacuum pump, e.g. the measurement of the critical backing pressure is only necessary

25、 for vacuum pumps which need a backing pump. All data that are measured on a vacuum pump, but not specified in this part of ISO 21360 (e.g. measurement of power consumption), are defined in the specific pump standard.2 Normative referencesThe following referenced documents are indispensable for the

26、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 3529-2, Vacuum technology Vocabulary Part 2: Vacuum pumps and related terms3 Terms and definitionsFor the p

27、urposes of this document, the terms and definitions given in ISO 3529-2 and the following apply.INTERNATIONAL STANDARD ISO 21360-1:2012(E) ISO 2012 All rights reserved 1BS ISO 21360-1:2012ISO 21360-1:2012(E)3.1volume flow rateqVqVtV=ddwhereV is volume;t is timeISO 80000-4:20064, 4-30EXAMPLE In the c

28、ontext of this part of ISO 21360, the volume flow rate is the volume of gas which, under ideal conditions, flows from the test dome through the pump inlet per time.NOTE 1 For practical reasons, the volume flow rate of a given pump and for a given gas is conventionally considered to be equal to the q

29、uotient of the throughput of this gas and of the equilibrium pressure at a given location. The volume flow rate is expressed in cubic metres per hour or litres per second.NOTE 2 The term “pumping speed” and symbol “S” are often used instead of “volume flow rate”.3.2inlet pressurep1, pd, pepressure a

30、t the inlet of the pump, measured at a defined location in the test dome3.3base pressurepbpressure obtained in the test dome after conditioning the vacuum pump and the test domeSee 5.4.NOTE The base pressure is the value which the pressure in the test dome approaches asymptotically. It is the lowest

31、 pressure obtainable with the pump, but there is no practical method of measurement or specification.3.4maximum working pressurep1maxhighest pressure on the inlet side that the vacuum pump and the driving device can withstand for a prolonged period of operation time without being damaged3.5backing p

32、ressurep3pressure at the outlet of a vacuum pump3.6critical backing pressurepcmaximum backing pressure for which the conditions are defined in the instruction manual or in a specific standard for the particular vacuum pump3.7compression ratioK0ratio of the backing pressure, p3, to the inlet pressure

33、, p1, of the vacuum pump without throughput, expressed by the equation:Kpp031=2 ISO 2012 All rights reservedBS ISO 21360-1:2012ISO 21360-1:2012(E)3.8test domespecial vacuum vessel with precisely defined size, diameter and connection flanges on specified locations, used for standard performance data

34、measurements on vacuum pumps3.9throughputQamount of gas flowing through a duct, expressed by the equation:QpVtpqV=11wherep1is the (high) vacuum pressure on the inlet;qVis the volume flow rate of the test pump;t is time;V is the volume of the test dome3.10standard gas flow rateqVstdvolume flow rate a

35、t standard reference conditions, i.e. 0 C and 101 325 PaNOTE Standard reference conditions are defined in ISO 3529-1:19811, 1.0.2.4 Symbols and abbreviated termsSymbol Designation Unita inner diameter of the connection pipe between test pump and quick-acting valve (items 3 and 5 in Figure 6)mA cross

36、-section of the connection pipe between test pump and quick-acting valve (items 3 and 5 in Figure 6)m2C conductance m3/s (= 103l/s)d diameter of orifice mD inner diameter of test dome mDNnominal diameter of test dome mK0compression ratio of vacuum pump with zero throughput l length of the connection

37、 pipe between test pump and quick-acting valve (items 3 and 5 in Figure 6)mlmean free path mM molar mass of gas kg/molp0standard atmospheric pressure 101 325 Pa (defined in ISO 3529-1:19811, 1.0.2)Pap1(high) vacuum pressure on inlet Pa (or mbar) ISO 2012 All rights reserved 3BS ISO 21360-1:2012ISO 2

38、1360-1:2012(E)p1maxmaximum working pressure on inlet Pa (or mbar)p3vacuum pressure in backing line Pa (or mbar)pt1, pt2,pt3pressures in the test dome for the pump-down method, measured before and after time intervals t1, t2, t3Pa (or mbar)pb1, pb2, pb3base pressures Pa (or mbar)pccritical backing pr

39、essure Pa (or mbar)pd, pepressures in the test dome for the orifice method Pa (or mbar)Q gas throughput of vacuum pump Pal/s (or mbarl/s)Qrtest gas load Pal/s (or mbarl/s)qVvolume flow rate of test pump l/s (or m3/h)qVBPvolume flow rate of backing pump l/s (or m3/h)qVsccmvolume flow rate at standard

40、 reference conditions for gases, i.e. 0 C and 101 325 Pasccm (or cm3/min)qVstdvolume flow rate at standard reference conditions for gases, i.e. 0 C and 101 325 Pal/s (or m3/h)Qmaxmaximum gas throughput of vacuum pump which the pump can withstand without damagePal/s (or mbarl/s)R ideal gas constant 8

41、,314 J/(molK)T thermodynamic temperature KT0273,15 K (defined as 0 C in ISO 3529-1:19811, 1.0.2) KTDtemperature of the test dome KTftemperature of the flow meter Ku measurement uncertainty V volume of the test dome l, m3Vivolume of connection pipe between test pump and quick-acting valve (items 3 an

42、d 5 in Figure 6)l, m3d thickness of the orifice wall at the orifice diameter m5 Test methods5.1 Volume flow rate (pumping speed) measurement by the throughput method5.1.1 GeneralThe throughput method is the one most used for vacuum pumps and is applicable to all pressure ranges and pump sizes where

43、flow meters for gas throughput measurements are available with sufficient accuracy. The gas flow measuring ranges shall be chosen by multiplying the expected volume flow rate by the maximum and minimum working pressure of the test pump.4 ISO 2012 All rights reservedBS ISO 21360-1:2012ISO 21360-1:201

44、2(E)All measuring devices shall be calibrated either:a) in a traceable way to a vacuum primary or to a national standard, orb) by means of instruments of absolute measure which are traceable to the SI units and to which measurement uncertainties can be attributed.In the case of calibrated measuring

45、instruments, there should exist a calibration certificate in accordance with ISO/IEC 170253.5.1.2 Test dome for the throughput methodFor these measurements, use a test dome as shown in Figure 1 with the same nominal diameter, DN, as that of the pump inlet. The face of the dome opposite the inlet fla

46、nge may be flat, conical or slightly curved, with the same average height above the flange as the flat face. Three flanges are preferable for pressure measurement at a height of D/2 above the bottom flange if more than one pressure gauge is used. The diameter of these flanges should be greater than

47、or equal to the flanges of the gauges used, and their mounting dimensions shall be noted. No measuring port shall be located in the angle range 45 next to a gas inlet port. The connection pipes between flange and dome shall not protrude beyond the dome wall on the inside, with the exception of the g

48、as inlet pipe.If necessary for the test pump, the test dome shall be fitted with a device for bake-out that ensures uniform heating of the dome to achieve the base pressure.The volume of the test dome may depend on the pump type. Refer to the specific pump standard for details.For pumps with an inle

49、t flange diameter of less than DN= 100 mm, the diameter of the dome shall correspond to DN= 100 mm. The transition to the pump inlet flange shall be made through a 45 conical adaptor, as shown in Figure 1.Key1 gas inlet pipe and temperature measuring point for TD2 vacuum gauge and mass spectrometer connectionsD inner diameter of test dome, in metresFigure 1 Test dome for the throughput method ISO 2012 All rights reserved 5BS ISO 21360-1:2012ISO 21360-1:2012(E)5.1.3 Experimental setupSee Figure 2.T