Sieve - Mechanical Vibratory Sieving

Mechanical Vibratory Sieving

Mechanical vibratory sieves also commonly referred to as gyratory separators or screening machines, are a traditional part of processing dry bulk powders. They classify materials by separating them by particle size through a screen mesh. Using a combination of horizontal and vertical movements by means of a vibratory motor, they spread the material over a screen in controlled flow patterns and stratify the product. There are three main functions a vibratory sieve or separator can achieve:

• Check/safety screening: used for quality assurance by checking for foreign contaminants and oversized material and removing them from the product.
• Grading/sizing screening: used to grade or classify material into different particle sizes.
• Recovery screening: used to recover valuable materials in the waste stream for re-use.

Most machines vibrate at 1400 rpm, but by separating the motor from the rubber suspension in this type of design, it became possible to increase the operating speed of the machines up to 2800 rpm with high out-of-balance forces. This development led to increased efficiency of the sieve, enabling smaller diameter machines to be used without adversely affecting performance. For example, a 22” diameter machine operating at 2800 rpm can significantly out-perform a 48” diameter machine operating at 1400 rpm on materials which are traditionally difficult to screen.