Hand Sieving vs Using a Mechanical Shaker

https://www.globalgilson.com/sieve-sh...

Mechanical vs Hand Sieving
Particle size analysis by sieving is a method of separating and classifying granular materials that dates back to ancient times. Today, sieve analysis, used by material scientists, and engineers, determines particle size distribution for many materials to accurately meet quality control requirements.

Hand sieving is the most basic way to perform sieve analyses and is acceptable for applications where a high degree of efficiency, accuracy, and repeatability are NOT essential. Results are highly operator-dependent and can vary significantly.

Using the Hand Sieving Method

In using the hand sieving method, you first select a single test sieve with an opening required by the test method specifications such as a Gilson 8in ASTM E11 stainless steel compliance grade test sieve.

Place the sieve on to a sieve pan. Now place the clean dry test sample into the sieve. While holding the sieve and pan together in both hands, sieve the materials with a gentle circular motion, using your hand to repetitively tap on the size of the sieve to promote passage of near-size particles through the sieve mesh.

Continue sieving until no more than 1% by weight of the materials passes through the sieve during one minute of sieving action. Now, remove and weight the material remaining on sieve to calculate the percentage of the bulk sample.

Using a Sieve Shaker Method
Using a sieve shaker saves on testing time, automates particle agitation, and improves accuracy and repeatability.
There are 3 main types of Sieve Shakers: Mechanical, Vibratory, and Sonic. Choosing the right sieve shaker will have a significant effect on your test results.

Let’s take a closer look at different shaker types.

Mechanical Sieve Shakers have motor-driven mechanisms to agitate and reorient particles with orbital, circular, or rotational motions. AND some mechanical shakers also use repetitive tapping of the sieve stack to further reorient particles to prevent blinding and dead spots on the mesh surface 3:13 to enhance passage of particles and prevent the blinding of mesh openings by near-size sample particles. Mechanical Sieve Shakers are often the more affordable choice and may be sufficient for free-flowing materials that are coarser than #200 (75µm).

For example, the Glison SS-14 and SS-15 orbital sieve shakers which feature a back-and-forth lateral motion combined with up/down and tilting actions that moves the test specimen in orbit on the sieve cloth. These shakers are recommended primarily for No.4 to No.200 (4.75mm to 75µm) material size range but may be used with larger material sizes when specifications for sieve loading and sample quantities permit.
OR consider the Gilson SS-8 and SS-12 Tapping Sieve Shakers, which have a researched-based sieving action that produces sharp, repeatable separations quickly over a broad range of particle sizes and material types. These shakers have a superior circular rotation that prevents "dead spots" on the sieve mesh, plus a two-wat tapping action to mix, reorient, and redistribute near-size particles to clear the mesh openings.

Vibratory Sieve Shakers are ideal for powders and many fine granular materials including minerals, pharmaceuticals, metals, and cosmetics by using electromagnetic energy to evenly distribute test samples and encouraging fines to pass through the mesh.

For example, the Gilson SS-10 One-Touch Vibratory Shaker which combines the latest in electronic control with proven separation technology to ensure the maximum number of passing opportunities without the loud noise levels of mechanically operated shakers. The SS-10’s three-dimensional vibratory action with its programmable test cycle pause function and amplitude control, creates a fluid bed which evenly distributes the test sample across the sieve mesh as it continuously lifts and reorients particles.
Or consider the SS-3 Vibratory Sieve Shaker with its amplitude control and in-line solenoid-actuated tapping action to redistribute the sample on the sieve cloth and clear undersized particles from mesh openings.

Sonic Sieve Shakers, or sometime called Sonic Sifters use acoustic energy to create an oscillating column of air for agitation. Vertical and/or horizontal tapping assists in separation Rapid pulses of airlift each particle off the sieve cloth, causing it to reorient and land on a different opening to assist in particle separations.

For example, the Gilson GA-6 AutoSiever Sonic Sifter and GA-8 UltraSiever Sonic Sifter, uses continuous agitation of 3600 sonic pulses per minute with a vertical oscillating air column and with mechanical tapping, that lifts and re-orients particles.

So, as we can see, using a Gilson sieve shaker is the only choice where a high degree of efficiency, accuracy, and repeatability are essential.

https://www.globalgilson.com/sieve-sh...