For several years, people in the test sieving business have been grousing about the difficulty of making sure that a test sieve certification is what they need. Anyone who is working with close tolerances in the smaller particle sizes, like 300 microns and smaller, have serious issues in matching results from test sieve to test sieve.Read More
CSC Scientific Blog
Yes Harry, there is a Santa Clause. Or, more specifically, there really is a Holy Grail for ensuring consistent particle size analysis.
If you’ve been following along, you know it was proven by Pequeño and his family of 150 micron particles who tried to bust our friend Harry’s quality control by attempting to slip through the mesh in Harry’s test sieves and defeat sieve certification.
(If you missed this drama, check out previous posts in the Holy Grail series.)
Now that we have indeed confirmed that, yes, sieve calibration really is the Holy Grail that sieve testers have been looking for, let’s get to work and dive a little deeper. Let’s examine some methods of sieve calibration.
You may remember Pequeño and his family of very small 150 micron (150µ) particles being very determined to defeat sieve certification.
We continue to search for answers to the question "Is Sieve Calibration Really the Holy Grail?" As promised,we present Episode III of the Pequeño saga. You may remember him as a very small (150-micron) particle with many similar-sized family members who are determined to defeat sieve certification.
We get repeated queries about calibration of our DuNouy Ring Tensiometers. That makes me think that calibrating procedures to insure accurate surface tension measurment needs some clarification.
Is Sieve Calibration Really the Holy Grail? Part II: Inside a Sieve Test
As I start on this second installment of The Adventures of Pequeño: The 150 Micron Particle, I wonder why I get myself into these serial onslaughts. However, a promise is a promise, so I shall press on.
You will recall from Part I: Sieve Certification, our little friend Pequeño, a particle on a determined quest to make it through sieves -- particularly those through which he should be too large to pass. In this scenario, Pequeño along with some of his family and friends -- all small particles about 150 microns in size -- are on their way to a sieve test.
- Is your concrete going to be strong enough?
Will you chocolates taste right?
Will your washing powder flow and dissolve as advertised?
Is there dangerous residue in your pill stock?
Will the “frack sand” keep the fractures open?
Is my salt of the correct grade?
If these are not correct, serious consequences could result (e.g. spoiled product, returned batches, rework or scrap).
Within the catalog of questions we are asked is a category related to Calibrating duNouy Ring Tensiometers. The subject matter ranges from how, why and what is proven?
I guess the immediate and wise-assed answers are:
In April, we published an article in "Powder-Bulk Solids" comparing certification process veracity with a sieve calibration process using calibrated glass microspheres (or beads). The certification process merely indicates that a sieve mesh conforms to a standard that has a wide tolerance regarding mesh openings. It is performed on a small number of openings. On the other hand, calibration using the calibrated beads results in a number representing the mean opening -- a result generated by actually performing a test encompassing at least 80% of the mesh openings.
Customers want Bostwick Consistometer Calibrations.
When told that CSC Scientific does not calibrate Bostwick Consistometers, people ask . “Then how can I calibrate my consistometer and where can I get a calibration standard?”.