BS ISO 12500-3-2009 Filters for compressed air - Test methods - Particulates《压缩空气过滤器 试验方法 微粒物质》.pdf

1、BS ISO12500-3:2009ICS 23.100.60NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDFilters for compressedair Test methodsPart 3: ParticulatesThis British Standardwas published underthe authority of theStandards Policy andStrategy Committee on 30November 2009. BSI 20

2、09ISBN 978 0 580 58708 5Amendments/corrigenda issued since publicationDate CommentsBS ISO 12500-3:2009National forewordThis British Standard is the UK implementation of ISO 12500-3:2009.The UK participation in its preparation was entrusted to TechnicalCommittee MCE/8, Compressors, pneumatic tools, p

3、neumatic machinesand vacuum technology.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British

4、Standard cannot confer immunityfrom legal obligations.BS ISO 12500-3:2009Reference numberISO 12500-3:2009(E)ISO 2009INTERNATIONAL STANDARD ISO12500-3First edition2009-07-01Filters for compressed air Test methods Part 3: Particulates Filtres pour air comprim Mthodes dessai Partie 3: Particules BS ISO

5、 12500-3:2009ISO 12500-3:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the ed

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8、t the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2009 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

9、either ISO at the address below or ISOs member body in the 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 2009 All rights reservedBS ISO 12500-3:2009

10、ISO 12500-3:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Units and symbols 2 5 Reference conditions . 2 6 Summary of test methods 3 7 Test requirements. 3 8 Test methods. 5 9 Data reporting . 11 1

11、0 Uncertainty 11 Annex A (informative) Sample test report form. 12 Bibliography . 15 BS ISO 12500-3:2009ISO 12500-3:2009(E) iv ISO 2009 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The

12、 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 and non-gove

13、rnmental, 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 Directives, Part 2. T

14、he 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 casting a vot

15、e. 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 12500-3 was prepared by Technical Committee ISO/TC 118, Compressors and pneumatic tools, machi

16、nes and equipment, Subcommittee SC 4, Quality of compressed air. ISO 12500 consists of the following parts, under the general title Filters for compressed air Test methods: Part 1: Oil aerosols Part 2: Oil vapours Part 3: Particulates A Part 4 dealing with water removal is under development. BS ISO

17、12500-3:2009ISO 12500-3:2009(E) ISO 2009 All rights reserved vIntroduction Particulates are a typical contaminant found in compressed air streams. Particulate filters are designed to remove particulates from compressed air. The most important performance characteristics are the ability of the filter

18、 to remove particulates from the air stream and the amount of pressure drop caused by the filter as compressed air flows through it. This part of ISO 12500 provides a means of comparing the performance of filters. BS ISO 12500-3:2009BS ISO 12500-3:2009INTERNATIONAL STANDARD ISO 12500-3:2009(E) ISO 2

19、009 All rights reserved 1Filters for compressed air Test methods Part 3: Particulates 1 Scope This part of ISO 12500 provides a guide for choosing an appropriate method of determining the solid particulate removal efficiency rating by particle size of filters used in compressed air systems. This par

20、t of ISO 12500 specifies the layouts and procedures for testing these filters. Measurement methods are recommended based on the size range of the particulates that the filter being tested has been designed to remove. The test is performed as a “type-test” on filters as being representative of a rang

21、e. The following two particle diameter size ranges are identified in this part of ISO 12500: fine filter range 0,01 m to D (2) where D is the pipe bore, expressed in millimetres. 8 Test methods 8.1 General A minimum of three complete test cycles should be run and the efficiency results averaged for

22、each particle size range under consideration. For efficiency measurement, a new filter shall be used each time. The measurement shall not be repeated with a filter element that has already been tested, as it is already loaded with either solid or liquid test agent. The pressure drop of the test filt

23、er assembly shall be measured and recorded at the start and end of the test. Care should be exercised to minimize any effects on the measured efficiency of the device due to particles from sources such as the device itself, test equipment or the cleanliness of the air supplied. The filter shall be f

24、itted and operated in the test stand in its intended final operating orientation. The bore of the pipe shall be continuous and of the same size as that connected to the filter under test, at least in the portion between the upstream sampling point and downstream sampling point. The test stand shall

25、be designed to minimize particle losses. Dust-delivery tubing and sampling line lengths shall be kept to a minimum. For fine-filter testing, the pipework shall be constructed from stainless steel and be electrically grounded to assist with particle transportation and prevent static charge. 8.2 Fine

26、filter testing 8.2.1 Fine filter equipment arrangement A typical test assembly for fine filters is shown in Figure 2. The aerosol generation, sample counting and method statement can be found in EN 1822-2 and EN 1822-5. If two different particle-measuring systems are used as represented in Figure 2,

27、 it is necessary that the counting efficiency of each particle-measuring system be known. If a particle-measuring system with a lower counting efficiency is used for the upstream measurement, then the evaluation of the filter efficiency is understated; if it used for the downstream measurement, then

28、 it is overstated. As a consequence, it is necessary to correct the results based on the counting efficiency of each particle-measuring system. The zero counting rate of the particle-measuring system shall also be considered. Thus, for example, the particle-measuring system with the lower zero count

29、ing rates shall be used for downstream measurement. If it is known that the upstream conditions are stable and/or are controlled by another measuring device, then the measurement can be carried out with only one particle-measuring system, which then avoids the problems mentioned earlier. The procedu

30、re then involves taking the upstream measurement first in order not to operate the particle-measuring system within coincidence and then taking the downstream measurement, both times using the same particle-measuring system. BS ISO 12500-3:2009ISO 12500-3:2009(E) 6 ISO 2009 All rights reservedKey 1

31、compressed air source 12 differential pressure gauge 2 full-flow ball valve 13 dilution/diffuser system 3 pressure reducing valve 14 particle sensing/measuring 4 pressure sensing/measuring 15 upstream pressure measuring tube 5 flow sensing/measuring 16 downstream pressure measuring tube 6 particle g

32、enerator/neutralizer 17 test filter 7 particle mixer 18 downstream iso-kinetic sampling 8 temperature sensing/measuring 19 multi-turn flow control valve 9 pressure sensing/measuring 20 silencer 10 upstream iso-kinetic sampling 21 ambient temperature sensing/measuring 11 pressure sensing/measuring aF

33、or further details of the particle generation and charge neutralization system, see EN 1822-2. bThe selection of a dilution/diffuser system is dependent on system pressure, particle concentration, filter efficiency and particle counting equipment design. Consult the manufacturer for further advice.

34、cThe particle sensing/measuring devices are required to have matched efficiencies. dDetails of the construction of the measuring tubes are given in ISO 7183:2007, Annex D. Figure 2 Typical fine filter test arrangement 8.2.2 Calculating fine filter efficiency Filtration efficiency, FE, expressed as a

35、 percentage, can be calculated from Equation (3): Edownup( ) 1 ( ) ( ) 100FCC= (3) where Cdown() is the particle concentration downstream (as a function of the particle diameter) of filter under test; Cup() is the particle concentration (as a function of the particle diameter) upstream of filter und

36、er test; is the particle diameter. BS ISO 12500-3:2009ISO 12500-3:2009(E) ISO 2009 All rights reserved 7Results may be presented as a curve of efficiency versus particle size. An example curve is given in Figure A.1. 8.3 Coarse filter testing 8.3.1 General The efficiency of coarse filters is establi

37、shed by collecting the dust on suitable membranes. The particles are washed from the membrane to suspend them in solution for analysis by a suitable particle counter. It is necessary that the counter be able to count particles over the 0,5 m to 100 m range when suspended in a suitable solution. The

38、membranes are composed of cellulose acetate or cellulose nitrate with a pore size that shall not exceed 20 % of the nominal rating of the filter under test. The membrane housing shall give adequate support to the membrane and limit the face approach velocity to that specified by the membrane manufac

39、turer. The flow rate used for the test shall be that specified by the filter manufacturer. If no flow is specified, it shall be taken from Table 2. Table 2 Test flow at rated conditions Supply pressure kPa (e) bar (e) Port size Flow rate L/s 1/8 2,7 1/4 6,3 3/8 13,9 1/2 25,8 3/4 38,7 1 72 1 1/4 147

40、1 1/2 223 700 (7.0) 2 431 8.3.2 Challenge dust characterisation Suspend an accurately known mass of the challenge dust, msample, in a suitable liquid for the counter used in the test. Establish the particle count, Nsample(), over the particle size range of 0,5 m to 100 m, where Nsample() is the coun

41、t for a given particle size of the sample. NOTE The mass of challenge dust and the volume of liquid depend upon the characteristics of the counter and are confirmed by experience. 8.3.3 Dust injection Injection of ISO fine test dust into a pressurized compressed-air system at 700 kPa (e) 7 bar (e) i

42、s not possible using the traditional method of dust injection via an ISO dust injector. Another method of aerosol delivery into the system is required for a pressurized system. For example, one method employs a syringe filled with the test dust driven by a stepper motor to precisely deliver the dust

43、 into BS ISO 12500-3:2009ISO 12500-3:2009(E) 8 ISO 2009 All rights reservedthe throat of a venturi. The high velocity of the air in the throat of the venturi disperses the particles into the carrier gas stream. A dust injection rate of approximately 0,25 mg/L of air at reference conditions shall be

44、used over a test period of 15 min. It can be necessary to adjust this injection rate depending on the test-filter efficiency. Low efficiencies can give an excessive dust loading on the membrane. Over the period of the test run, record the increase of differential pressure across the filter under tes

45、t. For the test to be valid, the increase in differential pressure shall not exceed 50 hPa 50 mbar. It is necessary to determine the mass, minjected, of dust injected. The determination of minjecteddepends on the method of dust injection. For example, the mass injected can be calculated from the tes

46、t filter mass gain, mfilter, and the mass of dust in the downstream air flow, mdown. In full-flow sampling, mdownis equal to mmem, the mass gain of the membrane. In the case of isokinetic sampling, Equation (4) applies: down mem isomqT qt= (4) where q is the full test flow, expressed in litres per s

47、econd; qisois the isokinetic sampling flow, expressed in litres per second; T is the dust-injection time, expressed in seconds; t is the isokinetic sampling time, expressed in seconds. 8.3.4 Membrane particle analysis 8.3.4.1 Particle-counter method Wash the particles collected on the membrane using

48、 a solution appropriate for the counter and establish the membrane particle count, Nmem(), over the size range 0,5 m to 100 m, where Nmem() is the count for a given particle size. Repeat the washing to check the efficiency of particle removal. If necessary, add the counts for each particle size. 8.3

49、.4.2 Microscope method The system employs a gridded membrane with a classification suitable for the intended measurement range, in conjunction with a microscope. The method is used to measure particles of diameter in the range 0,5 m to 100 m. To determine particle concentration by microscopy, the method described in BS 3406-4 should be employed. The optimum duration of a test measurement may be determined after an initial test to determine the approximate particle concentration present