Select the Right Sieve Shaker for Your Application
BY Ben Backus
Sieve shakers save considerable time and improve accuracy and repeatability of particle size tests when compared to hand-shaking methods by increasing the opportunities for particle passage. Modern sieve shakers can be categorized by their actions into three basic types: mechanical, vibratory or sonic. Let’s take a look at how to select the ideal shaker based on the materials with which you’re working.
Mechanical sieve shakers have motor-driven mechanisms to agitate and reorient particles with orbital, circular or rotational motions. This motion can be enhanced with tapping action. Non-Tapping mechanical sieve shakers are often more affordable and may be sufficient for free-flowing materials that are easily sieved and coarser than #200 (75 µm).
It’s best to use a tapping mechanical sieve shaker when you’re looking for the sharpest separation of materials from 2 inches (50 mm) to as fine as No.635 (20 µm). These models work well for a variety of materials, especially those with a wide range of particle sizes and a higher percentage of fines.
Vibratory sieve shakers use quiet, electromagnetic energy to agitate particles. A proper vibration setting creates a fluid, moving bed of the sample material, evenly distributing material across the mesh as it lifts and reorients particles, ensuring the maximum number of passing opportunities. Vibration levels can be adjusted on most models to suit the nature of the material, and a brief pause can often be programmed in to enhance particle passage.
It’s best to use a vibratory sieve shaker for materials between 1 inch (25 mm) and No.635 (20 µm). It’s ideal for granular and fine materials, especially dry powders. The quieter actions of vibratory shakers often make them a better choice where excessive noise can be a factor.
Sonic sieve shakers use up to 3,600 sonic energy pulses per minute from an audio generator, creating an oscillating air column enclosed by the sieve stack. Continuous agitation excites and reorients particles to mesh surfaces. Tapping is selectable from the bottom or the sides of the sieve stack, or both. Energy input can be tuned for different types of materials.
Sonic sieve shakers are often used to perform precision separations on small volume and particle size specimens as fine as 3 µm, making these shakers especially effective for powders, fine granular materials and “problem” materials. Precision electroformed sieves with very close tolerances are often used in these applications.
Selecting the proper sieve shaker can be a challenging process, and it’s important to understand that not all sieve shakers are the same.