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1、 Reference number ISO 21360:2007(E) ISO 2007 INTERNATIONAL STANDARD ISO 21360 First edition 2007-06-01 Vacuum technology Standard methods for measuring vacuum-pump performance General description Technique du vide Mthodes normalises pour mesurer les performances des pompes vide Description gnrale Co
2、pyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) PDF disclaimer This PDF f
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5、creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT IS
6、O 2007 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 either ISO at the address below or ISOs member body in the
7、 country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reserved Copyright International Organization for Standardization Provided by IHS und
8、er license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) ISO 2007 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative r
9、eferences. 1 3 Terms and definitions. 2 4 Symbols and abbreviated terms . 3 5 Test Methods. 4 5.1 Volume flow rate (pumping speed) measurement with the throughput method . 4 5.2 Volume flow rate (pumping speed) measurement with the orifice method 8 5.3 Volume flow rate (pumping speed) measurement wi
10、th the pump-down method 13 5.4 Measurement of the base pressure 18 5.5 Measurement of the compression ratio and the critical backing pressure 19 Annex A (informative) Mean free path of some important gases 23 Annex B (informative) Measuring uncertainties 24 Bibliography. 27 Copyright International O
11、rganization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) iv ISO 2007 All rights reserved Foreword ISO (th
12、e 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. Each member body interested in a subject for which a technical committ
13、ee 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 International Electrotechnical Commission (IEC) on all matters of electrotechn
14、ical 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 Standards adopted by the technical committees are circulated to the member
15、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 patent rights. ISO shall not be held responsible for identifying
16、any or all such patent rights. ISO 21360 was prepared by Technical Committee ISO/TC 112, Vacuum technology. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo r
17、eproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) ISO 2007 All rights reserved v Introduction This International Standard is a basic standard for measuring the performance data of vacuum pumps. The methods described here are well known from existing national and in
18、ternational standards. In developing this International Standard, the aim was to provide one single document containing the measurements of performance data of vacuum pumps and to simplify the future development of specific vacuum pump standards. Specific vacuum pump standards will contain a suitabl
19、e selection of measurement methods from this basic standard in order to determine the performance data, limiting values and specific operational conditions on the basis of the specific properties of the particular kind of pump. Whenever a discrepancy exists between the basic standard and the specifi
20、c standard, it is the specific standard which is valid. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license
21、from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO
22、 21360:2007(E) ISO 2007 All rights reserved 1 Vacuum technology Standard methods for measuring vacuum-pump performance General description 1 Scope This International Standard is a basic standard which defines three different methods for measuring the volume flow rate and one method each for measurin
23、g the base pressure, the compression ratio and the critical backing pressure of a vacuum pump. The first method 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
24、 measurement of gas throughput may be complicated or inexact. For this reason, two other methods are described 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 occurring at very sma
25、ll inlet pressures (in the high and ultra-high vacuum). It is based on measuring the ratio of pressures in a two-chamber test dome where 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 aut
26、omated measurement. It is based on the evacuation of a large vessel. The volume flow rate is calculated from two pressures, 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 duri
27、ng the pumping interval and increasing flow resistance in the connection line between test dome and pump caused by 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 prop
28、erties of the specific kinds of vacuum pump, e.g. the measurement of the critical backing pressure is only necessary for vacuum pumps which need a backing pump. All data that is measured on a vacuum pump but not described in this International Standard (e.g. measurement of power consumption) is defi
29、ned in the specific pump standard. 2 Normative references The 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)
30、applies. ISO 3529-1, Vacuum technology Vocabulary Part 1: General terms ISO 3529-2, Vacuum technology Vocabulary Part 2: Vacuum pumps and related terms Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie
31、 Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) 2 ISO 2007 All rights reserved 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 3529-2 and the following apply. 3.1 volume
32、 flow rate qV volume of gas which, under ideal conditions, flows from the test dome through the pump inlet per unit time NOTE 1 For practical reasons, however, the volume flow rate of a given pump and for a given gas is conventionally considered to be equal to the quotient of the throughput of this
33、gas and of the equilibrium pressure at a given location. The units adopted for the volume flow rate are cubic metres per hour (m3/h) or litres per second (l/s). NOTE 2 The term “pumping speed” and symbol “S” are often used instead of “volume flow rate”. 3.2 inlet pressure p1, pd, pe pressure at the
34、inlet of the pump, measured at a defined location in the test dome 3.3 base pressure pb pressure obtained in the test dome after conditioning the vacuum pump and the test dome See 5.4. NOTE The ultimate pressure is the value which the pressure in the test dome approaches asymptotically. It is the lo
35、west pressure obtainable with the pump, but there is no practical method of measurement or specification. 3.4 maximum working pressure p1max highest pressure on the inlet side that the vacuum pump and the driving device can withstand for a prolonged period of operation time without being damaged 3.5
36、 backing pressure p3 pressure at the outlet of a vacuum pump 3.6 critical backing pressure pc maximum backing pressure for which the conditions are defined in the instruction manual or in a specific standard for the particular vacuum pump 3.7 compression ratio K0 ratio of the backing pressure, p3, t
37、o the inlet pressure, p1, of the vacuum pump without throughput, expressed by the following equation: 3 0 1 p K p = Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24
38、 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) ISO 2007 All rights reserved 3 3.8 test dome special vacuum vessel with precisely defined size, diameter and connection flanges on specified locations, used for standard performance data measurements on vacu
39、um pumps 3.9 throughput Q amount of gas flowing through a duct, expressed by the following equation: 1 1 V p V Qp q t = where p1 is the (high) vacuum pressure on the inlet; qV is the volume flow rate of the test pump; t is time; V is the volume of the test dome. 3.10 standard gas flow rate qVstd vol
40、ume flow rate at standard reference conditions for gases in accordance with ISO 3529-1 4 Symbols and abbreviated terms Symbol Designation Unit a inner diameter of the connection pipe between test pump and quick-acting valve (items 3 and 5 in Figure 6) m A cross-section of the connection pipe between
41、 test pump and quick-acting valve (items 3 and 5 in Figure 6) m2 C conductance m3/s (= 103 l/s) d diameter of orifice m D inner diameter of test dome m DN nominal diameter of test dome m K0 compression ratio of vacuum pump with zero throughput l length of the connection pipe between test pump and qu
42、ick-acting valve (items 3 and 5 in Figure 6) m l mean free path m L thickness of the orifice wall at the orifice diameter m M molar mass of gas kg/mol p0 101 325 Pa in accordance with ISO 3529-1 Pa p1 (high) vacuum pressure on inlet Pa (or mbar) p1max maximum working pressure on inlet Pa (or mbar) C
43、opyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 06/18/2007 22:29:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21360:2007(E) 4 ISO 2007 All rights re
44、served p3 vacuum pressure in backing line Pa (or mbar) pt1, pt2, pt3 pressures in the test dome for the pump-down method, measured before and after time intervals t1, t2, t3 Pa (or mbar) pb1, pb2,.pb3 base pressures Pa (or mbar) pc critical backing pressure Pa (or mbar) pd, pe pressures in the test
45、dome for the orifice method Pa (or mbar) Q gas throughput of vacuum pump Pal/s (or mbarl/s) Qr test gas load Pal/s (or mbarl/s) qV volume flow rate of test pump l/s (or m3/h) qVB volume flow rate of backing pump l/s (or m3/h) qVsccm volume flow rate at standard reference conditions for gases in acco
46、rdance with ISO 3529-1 sccm (or cm3/min) qVstd volume flow rate at standard reference conditions for gases in accordance with ISO 3529-1 l/s (or m3/h) Qmax maximum gas throughput of vacuum pump which the pump can withstand without damage Pal/s (or mbarl/s) R ideal gas constant 8,314 J/(molK) T therm
47、odynamic temperature K T0 273,15 K in accordance with ISO 3529-1 K TD temperature of the test dome K Tf temperature of the flow meter K u measurement uncertainty V volume of the test dome l, m3 Vi volume of connection pipe between test pump and quick-acting valve (items 3 and 5 in Figure 6) l, m3 5
48、Test Methods 5.1 Volume flow rate (pumping speed) measurement with the throughput method 5.1.1 General The throughput method is the one most used for vacuum pumps and is applicable for all pressure ranges and pump sizes where flow meters for the gas throughput measurements are available with sufficient accuracy. The gas flow measuring ranges shall be chosen by multiplying the expected volume flow rate with the maxim