ASTM F660-83(1993)

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Designation: F 660 – 83 (Reapproved 1993)
Standard Practice for
Comparing Particle Size in the Use of Alternative Types of
Particle Counters
This standard is issued under the fixed designation F 660; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope an Optical Particle Counter
F 662 Method for Measurement of Particle Count and Size
1.1 This practice provides a procedure for comparing the
Distribution in Batch Samples for Filter Evaluation Using
sizes of nonspherical particles in a test sample determined with
an Electrical Resistance Particle Counter
different types of automatic particle counters, which operate on
F 796 Practice for Determining the Performance of a Filter
different measuring principles.
Medium Employing a Single-Pass, Constant-Rate, Liquid
1.2 A scale factor is obtained by which, in the examination
Test
of a given powder, the size scale of one instrument may be
multiplied to agree with the size scale of another.
3. Summary of Practice
1.3 The practice considers rigid particles, free of fibers, of
3.1 After calibrating an automatic particle counter with
the kind used in studies of filtration, such as: commercially
standard spherical particles, such as latex beads, the instrument
available test standards of quartz or alumina, or fly ash, or
is presented with a known weight of filtration-test particles
some powdered chemical reagent, such as iron oxide or
from which is obtained the data: cumulative number of
calcium sulfate.
particles, (N, as a function of particle diameter, d; and a plot
1.4 Three kinds of automatic particle counters are consid-
of these data is made on log-log paper.
ered:
3.2 The plot from the results of one kind of instrument is
1.4.1 Image analyzers, which view stationary particles un-
placed over the plot from another and one plot is moved along
der the microscope and, in this practice, measure the longest
the particle-diameter axis until the two separate curves coin-
end-to-end distance of an individual particle.
cide. (If the two separate curves cannot be made to coincide,
1.4.2 Optical counters, which measure the area of a shadow
then this practice cannot be used.)
cast by a particle as it passes by a window; and
3.3 The magnitude of the shift from one diameter scale to
1.4.3 Electrical resistance counters, which measure the vol-
the other provides the scale-conversion factor.
ume of a particle as it passes through an orifice in an
3.4 Any of the three particle counters in 1.4 can provide the
electrically conductive liquid.
frame-of-reference measurement of particle diameter.
1.5 This practice also considers the use of instruments that
3.5 An alternative reference is the Stokes diameter, as
provide sedimentation analyses, which is to say provide
mentioned in 1.5.
measures of the particle mass distribution as a function of
Stokes diameter. The practice provides a way to convert mass
4. Significance and Use
distribution into number distribution so that the meaning of
4.1 This practice supports test methods designed to evaluate
Stokes diameter can be related to the diameter measured by the
the performance of fluid-filter media, for example, Practice
instruments in 1.4.
F 796 wherein particle size distributions are addressed and at
1.6 This standard does not purport to address all of the
the same time this practice provides a means to compare size
safety problems, if any, associated with its use. It is the
measurements obtained from several different types of instru-
responsibility of the user of this standard to establish appro-
ments.
priate safety and health practices and determine the applica-
4.2 The factor for converting one kind of diameter scale to
bility of regulatory limitations prior to use.
another is only valid for the specific test particles studied.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Automatic Particle Counters:
F 661 Practice for Particle Count and Size Distribution
5.1.1 Any, or all, of the three types are employed:
Measurement in Batch Samples for Filter Evaluation Using
5.1.1.1 The Image Analyzer—This instrument counts par-
ticles by size as those particles lie on a microscope slide. In this
This practice is under the jurisdiction of ASTM Committee F-21 on Filtration
and is the direct responsibility of Subcommittee F21.10 on Liquid Filtration.
Current edition approved Jan. 28, 1983. Published March 1983. 2
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
F 660
practice, size means the longest end-to-end distance. This
diameter, in the examples to follow, is designated d .
e
5.1.1.2 The Optical Counter—This instrument measures the
area of a shadow cast by a particle as it passes a window. From
that area the instrument reports the diameter of a circle of equal
area. This diameter is designated d . See Practice F 661.
o
5.1.1.3 The Electrical Resistance Counter—This instrument
measures the volume of an individual particle. From that
volume the instrument reports the diameter of a sphere of equal
volume. This diameter is designated d . See Method F 662.
v
5.2 Sedimentation Instruments—These instruments provide
a measure of the mass distribution of particles (as opposed to
the number distributions determined in 5.1). This diameter, the
Stokes diameter, is designated d .
s
6. Procedure
6.1 Calibrate each particle counter with standard, spherical
particles, following the instructions of the manufacturer of the
counter.
6.2 Present a known mass of particles to the counter. That is,
with the image analyzer present a known mass of particles to
a field of view; and, with the other counters present a liquid
suspension with a known mass concentration of particles.
6.3 In counting particles at the small-diameter end of the
(N = cumulative number of particles per unit mass of powder
spectrum, present at least three different, relatively small,
d = particle diameter (see 5.1)
masses of particles. In counting particles at the large-diameter
The solid line represents the “real” count. The broken lines represent failures
end, present at least three different, relatively large, masses.
to obtain correct counts because of either presenting too many particles to the
counter, a, or of presenting too few, b.
6.4
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