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Gilson Company, Inc.
Pans collect fines at the bottom of the sieve stack. Extended-
Rim pans are also available to insert into the middle of a
stack, allowing two samples to be tested at once.
Covers are not necessary with most Gilson sieve shakers,
but may be needed if using a different shaker or shaking
by hand. The Cover-with-Ring has a wire finger loop in the
center to facilitate removal.
Sieve Verification procedures should be in place to regularly
check working sieves as they age. Wire cloth stretches,
sags, or even tears, and abrasive materials reduce wire
diameter, causing an increase in opening size and loss
of accuracy over time. Periodic, controlled measurement
of openings helps determine sieve compliance. These
measurements can be taken directly, using calipers or an
optical comparator, or by testing a Standard Reference
Material on the working sieves.
Gilson Verification Services can be performed on any
sieve, used or new. An optical comparator with NIST
traceable calibration measures opening sizes and wire
diameters on each serial numbered sieve. Certification
reports include statistical analysis for the appropriate ASTM
or ISO grade. These services are available for all ASTM and
ISO sieve sizes and types, and are ordered by specifying
GV-60 or GV-62 for Inspection Sieve Verification, and GV-
65 or GV-63 for Calibration Sieve Verification. Sieves are not
included in the purchase price of the verification services.
To verify used sieves, contact a Gilson customer service
representative for shipping instructions.
Standard reference Materials (SRM's) are precision
glass beads or powders used on sieves for performance
testing. They are produced on equipment traceable to the
National Institute of Standards and Technology (NIST), or
European Community Bureau of Reference (BCR). SRM's
fit easily into internal quality programs following guidelines in
ASTM E 2427, Sieve Acceptance by Performance Testing.
User-Prepared Reference Materials can also be utilized
under E 2427 in the same manner as SRM's. Because
user materials are non-standard, they are not traceable
and require much more handling. In addition, the user must
determine acceptable tolerances for statistical analysis.
Sieve Shakers save considerable time and effort,
and demonstrate superior accuracy, consistency, and
repeatability compared to manual shaking methods for
particle sizing. Effective agitation lifts all particles off the
sieve cloth, reorients them, and allows them to be repeatedly
"tried" to different openings at different angles. Careful
review of shaker specifications allows optimal choices
for different materials and applications. Greater sample
volumes and large particle topsize may indicate selection
of Gilson Test-Master
, Testing Screen or Porta-Screen
®
models for efficient processing.
8.0 TeST SIeVe
VerIFICATION & SerVICeS
There have been extensive revisions to the newest version
of ASTM standard E 11, Specification for Wire Cloth and
Sieves for Testing Purposes. Gilson is leading the way in
educating our customers about the new specification and
making these new products available. The new specification
affects all test sieves and wire cloth, and changes the
way the mesh openings are evaluated by looking at the
statistical distribution of aperture sizes, rather than just the
average opening sizes. In addition to a more accurate and
reliable system of evaluation, the new system also allows
compatibility with ISO 3310-1 requirements. There are
now three grades, or classes of ASTM or ISO test sieves
available; Compliance, Inspection and Calibration.
• Compliance Test Sieves are manufactured with wire
cloth that has been inspected and measured in roll or
sheet quantities prior to being cut and mounted in the
individual sieve frames. Opening sizes are not measured
in individual sieves. Each Compliance sieve is supplied
with a certificate of manufacturing compliance, but no
statistical documentation is given. Compliance sieves are
designed for applications where a basic, reliable degree
of accuracy and repeatability are sufficient.
• Inspection Test Sieves have a specified number of
openings measured in each sieve after the cloth is
mounted in the frame. There is a 99% confidence level
that the standard deviation of these openings is within
the maximum allowed by ASTM. Inspection Sieves
are a good choice in applications where accuracy and
repeatability are critical. Each Inspection Sieve consists
of a Compliance Sieve with added Inspection Sieve
Verification service.
• Calibration Test Sieves have about twice as many
openings measured as Inspection Sieves. The higher
number of openings measured on each sieve increases
the confidence level to 99.73% that the standard deviation
of these openings is within the maximum allowed by
ASTM. Calibration Sieves should be used in applications
where a very high degree of accuracy is required. Each
Calibration Sieve consists of a compliance sieve with
added Calibration Sieve Verification service.
New Gilson Test Sieves are guaranteed to meet the
requirements of ASTM or ISO for Compliance, Inspection or
Calibration grades as ordered, but for continued assurance
of performance, procedures should be in place to regularly
check working sieves as they age. Wire cloth stretches,
sags, or even tears, and abrasive materials reduce wire
diameter, causing an increase in opening size and loss of
®
accuracy over time.
Page 13
1-Touch Vibratory Sieve Shaker: SS-10
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