Chemical Engineering April 2012 - 49

Another commonly used device for
sample reduction of free-flowing powders
is the chute riffler as shown in Figure
9. It consists of alternating chutes
where half of the material discharges
on one side and the second half on the
other. The total number of chutes represents
the number of increments defining
the sample. Although the sample
can be processed several times to inReferences
1.
Gy, Pierre, " Sampling Theory and Sampling
Practice. Heterogeneity, Sampling Correctness,
and Statistical Process Control " , 2nd
Ed., CRC Press, Boca Raton, 1993.
2. Pitard, Francis F., " Pierre Gy's Sampling Theory
and Sampling Practice: Heterogeneity,
Sampling Correctness, and Statistical Process
Control " , CRC Press, Boca Raton, 1993.
3. Allen, T., " Particle Size Measurement " , 4th
Ed., Chapman & Hall, London, 1990.
4. Turian, R.M., and Yuan, T.F., Flow of Sluries
in Pipepines, 3, 1977, AIChE J., Vol. 23, 3, pp.
232-243.
5. Trottier, Remi and Dhodapkar, Shrikant, and
Wood, Steward, Particle Sizing Across the
CPI, Chem. Eng., April 2010, pp. 59-65.
crease the number of total increments,
it will likely not match the number of
increments performed by the spinning
riffler. As such, the spinning riffler is
the best device for sample reduction
and should be used whenever possible.
Several standards dealing with powder
sampling are available from a number
of organizations. A comprehensive
list is provided in the box, p. 48.
Authors
Remi Trottier is a research
scientist in the Solids Processing
Discipline of Engineering
& Process Sciences
at The Dow Chemical Co.
(Phone: 979-238-2908; Email:
ratrottier@dow.com). He received
his Ph.D. in chemical
engineering from Loughborough
University of Technology,
U.K,, and M.S. and B.S.
degrees in Applied Physics
at Laurentian University, Sudbury, Ont. He has
more than 20 years of experience in particle
characterization, aerosol science, air filtration
and solids processing technology. He has authored
some 20 papers, has been an instructor
of the course on Particle Characterization at the
International Powder & Bulk Solids Conference/
Exhibition for the past 15 years.
Shrikant V. Dhodapkar is a
fellow in the Dow Elastomers
Process R&D Group at The
Dow Chemical Co. (Freeport,
TX 77541; Phone: 979-2387940;
Email: sdhodapkar@dow.
com). He received his B.Tech.
in chemical engineering from
I.I.T-Delhi (India) and his
M.S.Ch.E. and Ph.D. from the
University of Pittsburgh. During
the past 20 years, he has
published numerous papers on particle technology
and contributed chapters to several handbooks.
He has extensive industrial experience in powder
characterization, fluidization, pneumatic conveying,
silo design, gas-solid separation, mixing, coating,
computer modeling and the design of solids
processing plants. He is a member of AIChE and
past chair of the Particle Technology Forum.
Summary
Appropriate attention to sampling,
sample size reduction and data analysis
is the first step towards obtaining
reliable analytical results from a batch
[5]. To obtain a representative sample,
one must adhere to the golden rules of
sampling and follow the best practices
as outlined in this article.
■
Edited by Rebekkah Marshall
Whether you need to transport, analyze, weigh, batch,
mix, grind, dry, shape or package you'll fi nd the solution at...
Exhibition & Conference: May 8-10, 2012
Donald E. Stephens Convention Center * Rosemont, IL (adjacent to O'Hare Airport)
Featuring:
Meet Industry Leaders with Thousands of the Latest Processing Solutions:
* Accessories
* Conveyors and Elevators
* Dryers
* Dust Collection/Control
* Energy, Environmental &
Pollution Control
* Filtration/Separation
* Feeders
* Instrumentation & Controls
* Material Handling & Transportation
* Mixers & Blenders
* Packaging & Bagging
* Particle Enlarger & Formers
* Plant Maintenance/
Safety/Health Products
* Processing/Mixing/
Blending Equipment
* Size Reduction
* Storage
* Thermal Solids Processors
* Weighing Systems & Scales
...and much more
Get the free
mobile app at
http://gettag.mobi
Follow the tag to register or log on to:
PowderShow.com
Produced and managed by: UBM Canon
21377_CH_PTXi12
11444 W. Olympic Blvd. * Los Angeles, CA 90064-1549
Tel: 310/445-4200 * Fax: 310/996-9499
Circle 22 on p. 82 or go to adlinks.che.com/40266-22
ChemiCal engineering www.Che.Com april 2012 49
http://www.PowderShow.com http://www.gettag.mobi http://adlinks.che.com/40266-22 http://www.Che.Com
Chemical Engineering April 2012

Table of Contents for the Digital Edition of Chemical Engineering April 2012
