In our business, we use the word “sieve” to describe a piece of equipment that separates different sized particles using a woven wire screen. To others, “sieve” can mean something very different.
CSC Scientific Blog
Do You Re-Certify? Compare with a Master Stack? Check with Calibration Samples?
What Does Recertification Give?
The ASTM E-11 committee has done a great job of establishing three levels of testing. These levels show the probability of a sieve’s mesh to be within the permissible variations. These variations relate to the size of openings in wire-cloth used for test sieves.Read More
Topics: Sieve Shakers, Mid-Point Sieves, ASTM, Particle Size Analysis, Sieve Calibration, Sieve Certification, Sieve Testing, Sieving Process, Quiet sieve shakers, RoTap, sieving, test sieve equipment, sieve mesh
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
Sieves make understanding the world around us not just possible, but also easier.
And with the advancement of sieves, not only are we able to separate dry particle, but also sift molecules from fluid as well. With molecular sieves developed by MIT, we can now strip a molecule’s individual parts gives us a better understanding of how things come together and work, such as diseases or even DNA.
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.
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).
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.
The relative value of a sieve certification process vs a sieve calibration has perplexed me for a long time.