ASTM F658-00a(2006)
(Practice)Standard Practice for Calibration of a Liquid-Borne Particle Counter Using an Optical System Based Upon Light Extinction (Withdrawn 2007)
Standard Practice for Calibration of a Liquid-Borne Particle Counter Using an Optical System Based Upon Light Extinction (Withdrawn 2007)
SCOPE
1.1 This practice covers procedures for calibrating and determining performance of an optical liquid-borne particle counter (LPC) which uses an optical system based upon light extinction measurement. This practice is directed towards determination of accuracy and resolution of the LPC for characterizing the size and number of particles, which have been passed into the sample inlet of the LPC. Consideration of inlet sampling efficiency is not part of this practice.
1.2 The procedures covered in this practice include those to measure sample volume and flow rate, zero count level, particle sizing and counting accuracy, particle sizing resolution, particle counting efficiency, and particle concentration limit.
1.3 The particle size parameter reported in this practice is the equivalent optical diameter based on projected area of calibration particles with known physical properties dispersed in liquid. The manufacturer normally specifies the minimum diameter that can be reported by an LPC; the dynamic range of the LPC being used determines the maximum diameter that can be reported for a single sample. Typical minimum reported diameters are approximately 2 m, and a typical dynamic range specification will be approximately from 50 to 1.
1.4 The counting rate capability of the LPC is limited by temporal coincidence of particles in the sensing volume of the LPC and by the saturation level or maximum counting rate capability of the electronic sizing and counting circuitry. Coincidence is defined as the simultaneous presence of more than one particle within the LPC optically defined sensing zone at any time. The coincidence limit is a statistical function of particle concentration in the sample and the sensing zone volume when particle size is insignificant in comparison to the sensing volume dimensions. This limitation may be modified by the presence of particles with dimension so large as to be a significant fraction of the sensing zone dimension. The saturation level rate of the electronic counting circuitry shall be specified by the manufacturer and is normally greater than the LPC recommended maximum counting rate for the particle concentrations used for any portion of this practice.
1.5 Calibration in accordance with all parts of this practice may not be required for routine field calibration of an LPC unless significant changes have occurred in operation of the LPC or major component repairs or replacements have been made. The LPC shall then be taken to a suitable metrology facility for complete calibration. Normal routine field calibration may determine sample flow rate, zero count level, and particle sizing accuracy. The specific LPC functions to be calibrated shall be determined on the basis of agreement between the purchaser and the user. The maximum time interval between calibrations shall be determined by agreement between the purchaser and the user, but shall not exceed twelve months, unless LPC stability for longer periods is verified by measurements in accordance with this practice.
This standard may involve hazardous materials, operation, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
WITHDRAWN RATIONALE
This practice covers procedures for calibrating and determining performance of an optical liquid-borne particle counter (LPC) which uses an optical system based upon light extinction measurement. This practice is directed towards determination of accuracy and resolution of the LPC for characterizing the size and number of particles, which have been passed into the sample inlet of the LPC. Consideration of inlet sampling efficiency is not part of this practice.
Formerly under the jurisdiction of Committee E29 on Particle and Spray Characterization, th...
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F658–00a (Reapproved 2006)
Standard Practice for
Calibration of a Liquid-Borne Particle Counter Using an
Optical System Based Upon Light Extinction
This standard is issued under the fixed designation F658; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope significant fraction of the sensing zone dimension . The
saturationlevelrateoftheelectroniccountingcircuitryshallbe
1.1 This practice covers procedures for calibrating and
specified by the manufacturer and is normally greater than the
determining performance of an optical liquid-borne particle
LPC recommended maximum counting rate for the particle
counter (LPC) which uses an optical system based upon light
concentrations used for any portion of this practice.
extinction measurement. This practice is directed towards
1.5 Calibration in accordance with all parts of this practice
determination of accuracy and resolution of the LPC for
may not be required for routine field calibration of an LPC
characterizing the size and number of particles, which have
unless significant changes have occurred in operation of the
been passed into the sample inlet of the LPC. Consideration of
LPC or major component repairs or replacements have been
inlet sampling efficiency is not part of this practice.
made. The LPC shall then be taken to a suitable metrology
1.2 The procedures covered in this practice include those to
facility for complete calibration. Normal routine field calibra-
measure sample volume and flow rate, zero count level,
tion may determine sample flow rate, zero count level, and
particle sizing and counting accuracy, particle sizing resolu-
particle sizing accuracy. The specific LPC functions to be
tion, particle counting efficiency, and particle concentration
calibrated shall be determined on the basis of agreement
limit.
between the purchaser and the user. The maximum time
1.3 The particle size parameter reported in this practice is
intervalbetweencalibrationsshallbedeterminedbyagreement
the equivalent optical diameter based on projected area of
betweenthepurchaserandtheuser,butshallnotexceedtwelve
calibration particles with known physical properties dispersed
months, unless LPC stability for longer periods is verified by
in liquid. The manufacturer normally specifies the minimum
measurements in accordance with this practice.
diameterthatcanbereportedbyanLPC;thedynamicrangeof
1.6 This standard may involve hazardous materials, opera-
theLPCbeinguseddeterminesthemaximumdiameterthatcan
tion, and equipment. This standard does not purport to address
be reported for a single sample. Typical minimum reported
all of the safety concerns, if any, associated with its use. It is
diametersareapproximately2µm,andatypicaldynamicrange
the responsibility of the user of this standard to establish
specification will be approximately from 50 to 1.
appropriate safety and health practices and determine the
1.4 The counting rate capability of the LPC is limited by
applicability of regulatory limitations prior to use.
temporal coincidence of particles in the sensing volume of the
LPC and by the saturation level or maximum counting rate
2. Referenced Documents
capability of the electronic sizing and counting circuitry.
2.1 ASTM Standards:
Coincidence is defined as the simultaneous presence of more
D1193 Specification for Reagent Water
thanoneparticlewithintheLPCopticallydefinedsensingzone
D3195 Practice for Rotameter Calibration
at any time. The coincidence limit is a statistical function of
E20 Practice for Particle Size Analysis of Particulate Sub-
particle concentration in the sample and the sensing zone
stances in the Range of 0.2 to 75 µm By Optical Micros-
volume when particle size is insignificant in comparison to the
copy
sensing volume dimensions . This limitation may be modified
2.2 Other Documents:
by the presence of particles with dimension so large as to be a
Knapp, J. Z. and Abramson, L. R., “A New Coincidence Model for Single
ThispracticeisunderthejurisdictionofASTMCommitteeE29onParticleand
Particle Counters. I Theory and Experimental Verification,” Journal of Parenteral
Spray Characterization and is the direct responsibility of Subcommittee E29.02 on
Science and Technology, Vol 48, 1994, pp. 255-294.
Non-Sieving Methods.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2006. Published June 2006. Originally
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1999. Last previous edition approved in 2000 as F658–00a.
Standards volume information, refer to the standard’s Document Summary page on
Jaenicke, R., “The Optical Particle Counter: Cross-Sensitivity and Coinci-
the ASTM website.
dence,” Journal of Aerosol Science, Vol 3, 1972, pp. 95-111.
Withdrawn.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F658–00a (2006)
ANSI/NCSLZ540-1-1994 Laboratories and Measuring and 3.1.8 dilution ratio—whenpreparingparticlesuspensionsto
Test Equipment—General Requirements define the particle concentration limit (see 4.6 and 10.7), the
ISO 11171 Hydraulic Fluid Power—Calibration of Liquid dilution ratio is the ratio of the volume of the undiluted
Automatic Particle Counters suspension plus particle-free diluent to the volume of the
ANSI B93.20M-1972 Fluid Sample Containers— undiluted suspension.
Qualifying and Cleaning Methods
3.1.9 dynamic range—the particle size range in which the
ANSI/NFPA T2.9.6 R2-1998 Hydraulic Fluid Power—
LPC produces particle size data with both a lower and a upper
Calibration of Liquid Automatic Particle Counters. Na-
size boundary. The range may be expressed as a particle size
tional Fluid Power Association
ratio, when the lower size is known. When the LPC is
calibrated with monodisperse calibration particles, the typical
3. Terminology
lower size sensitivity of an LPC is 2 µm; the largest particle
3.1 Definitions of Terms Specific to This Standard:
size typically reported is approximately 125 µm. When the
3.1.1 calibration—measurement, reporting, and adjustment LPC is calibrated with a polydisperse calibration suspension,
if required, of an instrument in comparison with a certified
the typical lower size sensitivity of the LPC is approximately
standard material or instrument of known adequate accuracy. 2.5 µm and the largest size reported is approximately 50 µm.
Primarycalibrationiscarriedoutwithastandardmaterialwith
The difference in size ranges for monodisperse and polydis-
characteristics that are directly traceable to a recognized perse particle calibration results from the differences in physi-
standards agency. Secondary calibration is carried out using a
cal properties for the two particle types. The effect on the
methodrecognizedbyavoluntarystandards-producingagency,
dynamic range limitation of the limited large particle concen-
even if a reference material rather than a standard material is
tration for the polydisperse material is discussed in 8.2.
used for the calibration.
3.1.10 inlet flow—the sample flow that enters the LPC
3.1.2 calibration particles—two types of calibration par-
through the flow inlet. Flow rate is expressed as volume per
ticlesareusedtocalibratetheLPC.Thesizeorsizedistribution
unit time, at ambient temperature and pressure.
of the calibration particles shall be determined by procedures
3.1.11 lower sizing limit—thesmallestparticlesizeatwhich
traceable to a recognized standards laboratory. Monodisperse,
the LPC is capable of measuring with counting efficiency of
isotropicparticlesofknowndimensionandphysicalproperties
50 610%.
are used directly for size calibration. These are available in
3.1.12 monodisperse—a particle size distribution with rela-
diameters covering the operating range of most LPCs. When
tive standard deviation less than 5%. Polystyrene latex (PSL)
size calibration is carried out with polydisperse particles, the
particles are commercially available with this property in
particle size distribution is specified over the size range of
particle sizes ranging from less than 2 µm to greater than 80
concern,themassconcentrationofthepolydisperseparticlesin
µm.
the calibration suspension is known, and the reported particle
3.1.13 particle size—for calibration, particle size is either
population data are used to establish a calibration. The cali-
the modal diameter of the monodisperse calibration particle
bration particles are described further in 4.2, 10.3, and 10.4
suspension used for each size threshold definition or it is the
3.1.3 calibration suspension—a suspension of calibration
size associated with a specified cumulative particle population
particles with a known particle size distribution dispersed in a
when a polydisperse particle suspension is used. For applica-
clean liquid. The mass concentration of the particles may be
tion purposes, particle size is the diameter of a reference
specified and the particle concentration in specific size ranges
particle with known properties, which produces the same
can be determined from these data.
response from the LPC as the particle being measured.
3.1.4 coincidence—the simultaneous presence of more than
3.1.14 pulse height analyzer (PHA)—an electronic device
one particle within the sensing volume of the instrument,
for collecting and sorting electronic pulses by voltage level.
causing the instrument to report the combined signal from the
The output is a histogram with 64 to 4096 levels, (referred to
several particles as arising from a single larger particle.
as “channels”). A PHA may be built into an LPC or may be
3.1.5 concentration—number or mass of particles within a
connected to an LPC output test point. The PHAshall have at
specificsizerangeorequaltoandlargerthanaspecificparticle
least 64 channels and shall be capable of defining the voltage
size per unit volume of liquid at ambient temperature and
pulse level in any channel with 95% accuracy.
pressure.
3.1.15 relative standard deviation—a measure of the width
3.1.6 concentration limit—theupperconcentrationbynum-
of a particle size distribution data histogram. It is quantified in
ber per unit volume of liquid specified by the LPC manufac-
terms of the ratio of the standard deviation of the distribution
turer where the coincidence error is below 10%.Amaximum
to the mean of the distribution. It is normally expressed as a
concentration limit producing an error less than 10% may be
percentage.
chosen, as required.
3.1.16 resolution—a measure of the ability of an LPC to
3.1.7 counting effıciency—the ratio, expressed as a percent-
differentiatebetweenparticlesofnearlythesamesize;also,the
age,ofthereportedparticleconcentrationinagivensizerange
range of sizes, which an LPC would report for a particular
to the actual concentration in the measured suspension.
particle if its size was determined repeatedly. It can be
quantified as the ratio of the difference between the reported
and true relative standard deviations for a measured series of
AvailablefromtheAmericanNationalStandardsInstitute,11W.42ndSt.,13th
Floor, New York, NY 10036. monodisperse particles.
F658–00a (2006)
3.1.17 sampled flow—the fluid, which passes through the significant amount of light, then the polydisperse calibration
sensing volume of an LPC. The sampled flow may be either a material described in 8.2.2 should be used.
portionofortheentireinletflow.Sampledflowisexpressedas
4.2.1 Particle SizingAccuracy Based on Response to Mono-
volume per unit time, at ambient temperature and pressure.
disperse Calibration Particles—Asuspensionofmonodisperse
3.1.18 saturation level—the maximum counting rate of the
calibrationparticlesispreparedbydispersingtheseparticlesin
electronic circuitry at which accurate pulse amplitude sizing
clean liquid. The LPC samples a portion of this suspension.
data are produced. The counting rate depends upon both the
Measurement is made of the modal voltage of the Gaussian
particle concentration and the sampled flow rate.
pulse height distribution generated by the LPC for those
3.1.19 sensing volume—the portion of the illuminated vol-
particles. This process is repeated for monodisperse particle
ume in the LPC through which the sample passes and from
suspensionsinsizesthatallowdefinitionofthemodalvoltages
which absorbed light signals are collected by the LPC photo-
for several particle sizes within the LPC dynamic range. The
detector.
suspensions are diluted with clean liquid, as required, to keep
3.1.20 zero count rate—themaximumcountindicatedbyan
particle concentration sufficiently low so that the coincidence
LPC in a specified time period when the LPC is sampling
error is below 3%. The particle size and relative standard
liquid free of particles larger than the lower sizing limit of that
deviation of the calibration particles are measured before the
LPC. This is also referred to as“ false count rate” or “back-
sizing accuracy determination or the particle vendor reports
ground noise level.”
diameter data produced by measurement methods traceable to
a recognized national or international standards development
4. Summary of Practice
agency on size and relative standard deviation of the calibra-
4.1 Inlet Sample Volume and Flow Rate—Toreportsampled
tion particles. The LPC modal pulse amplitude response to the
particle concentration accurately, it is necessary to define the
calibration particle suspensions is recorded along with the
sample volume and to control the flow rate accurately. That
standard deviation of the LPC pulse data. Refer to 10.3 for a
flow rate may change if flow components in the LPC or in the
complete description of this procedure.
liquid feeding system are affected by long-term operation or
4.2.2 Particle Sizing Accuracy Based on Response to Poly-
become plugged by deposition of particulate material. The
disperse Particles With Known Particle Size Distribution—A
LPC flow is normally defined at a specific pressure and should
suspension of polydisperse calibration particles is prepared by
not be changed during measurements.Acalibrated volumetric
suspending a known weight of these particles in a known
flow measurement device is required which operates with a
volume of clean liquid. Extreme care is required when remov-
pressure drop small enough so that the LPC flow control
ing a sample of polydisperse particles from the container to
system is not loaded to the point where flow is degraded. If a
mass flowmeter is used, correction to volumetric flow m
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