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1、J IS JAPANESE INDUSTRIAL STANDARD Translated and Published by Japanese Standards Association Light scattering automatic particle counter ICs 19.120 Descriptors : particle size measurement, light, particulate air pollutants, diffusion (waves), optical measurement, continuous, counting Reference numbe
2、r : JIS B 9921 : 1997 (E) PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- B 9921 :1
3、997 Foreword This translation has been made based on the original Japanese Industrial Standard revised by the Minister of International Trade and Industry through deliberations at Japanese Industrial Standards Committee in accordance with the Industrial Standardization Law. Consequently JIS B 9921:1
4、989 is replaced with JIS B 9921:1997. Date of Establishment: 1976-05-01 Date of Revision: 1997-09-20 Date of Public Notice in Official Gazette: 1997-09-22 Investigated by: Japanese Industrial Standards Committee Divisional Council on General Machinery JIS B 9921 :1997, First English edition publishe
5、d in 1998-06 Translated and published by: Japanese Standards Association 4-1-24, Akasaka, Minato-ku, Tokyo, 107-8440 JAPAN In the event of any doubts arising as to the contents, the original JIS is to be the final authority. O JSA 1998 All rights reserved. Unless otherwise specified, no part of this
6、 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. Printed in Japan PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license wit
7、h JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- JAPANESE INDUSTRIAL STANDARD JIS B 9921: 1997 Light scattering automatic particle counter 1 Scope This Japanese Industrial Standard
8、specifies the light scattering automatic particle counter to obtain particle concentration in air by sucking air continuously and by measuring the particle sizes and the number of the airborne particles (hereafter referred to as “particle counter”). Remarks 1 The following standards are normative re
9、ferences to this Standard : JIS B 9922 JIS Z 8103 JIS Z 8122 JIS Z 8901 In this Standard the units and numerical values shown in accordance with traditional units and appended for informative reference. Clean work station Glossary of terms used in instrumentation Contamination control- Vocabulary Te
10、st powders and test particles 2 1 are in 2 JIS Z 8103, and the following definitions apply : Definitions For the purpose of this Standard, the definitions given in JIS Z 8122 and particle size division The selecting division range of particle size in the case where only small particles larger than t
11、he specific particle size are selected and the particle concentration or number of small particles are measured. The particle size division is expressed by particle size value. clean air The air filtered by air cleaner or the like to the extent that there is no obstacle to the measurement of particl
12、es. false counting The counted value indicated on the counter even though there is no particle within a measurable range in the measured air. counting efficiency From the ratio of reference particle concentration (Co) of small particles in sample air absorbed from sample absorption inlet of particle
13、 counter to the particle concentration (C) displayed by particle counter, the counting efficiency (v) is obtained by the following formula : C C O v= - x loo(%) counting loss The counting loss of number of small particles caused by passing two particles coincidentally through irradiation zone of lig
14、ht, or resolving time of electric circuit, etc. preheating time The time required for particle counter to actuate stably after putting- in of power source. maximum rated particle concentration The maximum particle concentration permitted for measurement as determined for each individual particle cou
15、nter. Remarks : If the particle concentration increases, the counting loss of particle counter increases, and the correct display is not performed, and therefore, it is required to determine the maximum rated particle concentration for each indi- PROTECTED BY COPYRIGHT Copyright Japanese Standards A
16、ssociation Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- 2 B 9921 : 1997 vidual particle counter. (8) air for test The air to be used for testing
17、 the performance of particle counter, in which PSL particles known in diameter are airborne in dry clean air. Remarks : PSL particles used in this Standard is the test particle 1 specified in JIS Z 8901. 3 The sample air with a definite flow rate from sample absorption opening passes through the zon
18、e irradiated by stabilized light source. Lights scattered forward or inside direction by individual airborne particles are converged into photoelectric element of photomultiplier or the like and converted to pulse state electric signal. Select particle size by analysis of pulse peak value by utilizi
19、ng that the peak value of pulse signal is proportional to scattering light quantity and the scattering light quantity and the airborne particle diameter are in a definite relation, further obtain number of passing small particles larger than a specific size by counting the number of selected pulses,
20、 and obtain the particle concentration by absorbed air volume in a definite measuring time and the selected number of small particles. Measuring principle 4 The particle counter shall, as shown in Fig. 1, have light source, air suction system, irradiation and converging optical system, photoelectric
21、 converting part, peak analysis part, internal reference light generating part as well as input-and-output terminal for test or be the construction having the equivalent performance thereto. However, the particle counter having single particle size division need not have an input-and-output terminal
22、 for test. Constitution Fig. 1. Example of constitution of particle counter 5 Specification and performance 5.1 Specifications 5.1.1 Measuring range The particle counter shall be capable of measuring particle concentration or number of small particles in one particle size division or several particl
23、es of 0.1 pm or greater airborne. 5.1.2 The measured results shall be marked by particle concentration or total number of small particles larger than a specific particle size relating to Marking of measured quantity PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS unde
24、r license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- 3 B 9921 : 1997 unit of an arbitrary air volume marked respectively by particles/m3 particlesfl or particles. unmistaka
25、ble judgment to that effect shall be performed. be obtained according to the following formula : Further, when counting has exceeded capacity of particle counter, a marking for In the case of obtaining particle concentration (C) from number of small particles, it shall N C=- : Puise peak value corre
26、sponding to peak center AV; : half-width u Fig.5 Example of output peak distribution (c) Carry out the similar measurement relating to not less than three particle size divisions, and draw the characteristic curve of di to vi as shown in Fig. 6. The curve shall be interpolated or extrapolated accord
27、ing to Mie theory( i ). Note () Relating to Mie theory, refer to explanation (not included in the english version). When the particle size becomes larger, pulse may appear in the response curve. Therefore, the plating shall be within a range in which the particle size is determined decisively. PROTE
28、CTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- 8 B 9921 : 1997 dr d2 d3 6 Particle size
29、 (di) Fig.6 Response curve (d) By using the counting pulse height V, corresponding to D, of particle size division obtained in (l), obtain the particle size D, corresponding thereto from the characteristic curve of Fig. 6 (refer to Fig. 7). Obtain the particle size division accuracy E by the followi
30、ng formula and examine whether it satisfies the requirement in 5.2.4. (e) D,-D, E (%)=- x100 D, / Curve of Fig. 6 Di Particle size (Dfl Fig. 7 Determination of particle size value PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Emplo
31、yees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- 9 B 9921 : 1997 (3) Resolving power of particle size the curve of Fig. 6 (refer to Fig. 8). Obtain dDj corresponding to half-width Avi from Obtain the reso
32、lving power of particle size b by the following formula : b(%)= - x100 Fig. 8 Determination of resolving power 6 . 3 . 5 Take the particle counter less than 0.2 V m in the minimum measurable particle size as A group, that of not less than 0.2 pm as B group, take for A group the condensation nucleus
33、counter or the counter having the performance equivalent or superior thereto as reference, for B group take the particle counter of A group as the reference and thereby obtain the counting efficiency. Carry out the test by connecting the particle counter to be tested and A group particle counter wit
34、h the distributing box for mixing air for test and clean air as shown in Fig. 9. Adjust the particle concentration while supervising according to counting value of particle counter to be reference, to the concentration under 5 % in both counting loss in the particle counter to be reference and parti
35、cle counter to be inspected, so that the average value of variation width of concentration during testing does not exceed Make the pipings to supply air for test to particle counter to be reference and particle counters to be inspected (plural) from distributing box from materials not causing electr
36、ostatic charging of equal length of 1 m or less and preliminarily confirm that even though the pipings are exchanged mutually, the counting efficiency of particle counter does not vary (refer to Annex 2). Obtain the counting efficiency r? in the case where PSL particle of minimum measurable particle
37、 size is contained in air for test and in the case where PSL particle of particle size of not less than 1.5 times and not more than 2 times thereto is contained, and examine whether it complies with the specification of 5.2.5 or not. When there is not the PSL particle equal to the minimum measurable
38、 particle size, use the PSL particle of the particle size nearest the minimum measurable particle size or larger than it. Counting efficiency 10 % of average value. PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001
39、, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproduction or networking permitted without license from IHS -,-,- 10 B 9921 : 1997 Air generator for test I I I I Clean air for dilution reference Fig.9 Test for counting efficiency Informative reference : Test of condensation nucleus c
40、ounter The test of conden- sation nucleus counter shall be in accordance with the following method. (1) Generation of air for test Generate PSL particles in the range of 0.02 tun to 0.5 vm in particle size by particle generator, make the equilibrium charging state by using radioactive isotope, and g
41、enerate single dispersion particles at arbitraty charge according to differential electric mobility classifier. Measure the concentration of this single dispersion particle according to electrometer. Test of counting efficiency Adjust the particle concen- tration to be used for measurement of counti
42、ng efficiency to approximately 5 x io8 particies/m35 x io2 particies/rni). Obtain the counting efficiency by measuring particle concentration of air for test simultaneously with conden- sation nucleus counter and electrometer and by taking the concentration obtained by electrometer as the reference.
43、 However, in the case of taking the condensation nucleus counter as the reference, use it in the particle size range of 100 % k 5 % in counting efficiency. 6.3.6 following. Counting loss The calculation of counting loss shall be in accordance with the (i) Determination of time for small particles to
44、 pass through irradiation zone Obtain the time for small particles to pass through irradiation zone according to calculation or to measurement by the following method. Take the air for test with airborne PSL particles of arbitrary particle size as the sample, and dilute to approximately 1/10 of maxi
45、mum rated particle concentration to suck in. Input the output pulse from particle counter into oscilloscope which is made the input level trigger mode and observe for approximately 10 s, obtain the output pulse time t according to the following formula and take it as the time for small particles to
46、pass through irradiation zone. where, t , : minimum time for small particles to pass through PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/15/2007 23:00:41 MDTNo reproducti
47、on or networking permitted without license from IHS -,-,- 11 B 9921 : 1997 irradiation zone t2 : maximum time for small particles to pass through irradiation zone However, the case of abnormally long pulses appearing sporadically shall be In this case, the frequency band o of oscilloscope shall comp
48、ly with excepted. 2n . Informative reference Fig. 1 Example of output pulse (2) Calculation of counting loss Calculate counting loss of small particles in the maximum rated particle concentration by using t obtained in (1) by the following formula : Ce= 1 -exp(-&tno) where, C, : counting loss : flow rate of sample air (m/s) t : time for small particle to pass through the irradiation no : maximum rated particle concentration (particles/m3) zone (s) Calculate the ratio of Ce and no and examine whether it complies with the specification of 5.