Compact and versatile industrial sieving equipment for separation and check-screening bulk solids and powders
To meet the modern demands of today’s solids handling industry, a range of automated, compact and high-performance sieving equipment is available. Despite vibratory equipment sometimes being perceived as a traditional method of separation, there are a range of modern solutions that provide powerful tools to achieving the highest levels of product quality, whilst also keeping an eye on the bottom line.
Vibratory sieves and separators have played a key role in the processing of dry bulk powders for many years, classifying materials by particle size through a screen mesh. Using a combination of horizontal and vertical movements, they spread the material over a screen in controlled flow patterns and stratify the product.
There are several functions a vibratory sieve or separator can achieve. Firstly, check-screening, often used for quality assurance by checking for foreign contaminants and oversized material and removing them from the product. Grading or sizing of product is another common method, where material is classified into different particle sizes. Finally, recovery screening is used to recover valuable materials in the waste stream for re-use.
For many years, industrial sieves were commonly known as being rectangular or square in shape, using a simple reciprocating ‘shaking’ movement to classify powders and granules. However, the introduction of circular screens, which offered a much more efficient usage of screen area with circular product movement, has resulted in increased capacity per unit mesh area.
These circular vibratory sieves have continued to evolve. With major advances in technology such as ultrasonic sieving, and manufacturing methods of component parts continuing to evolve, it has become commonplace for machines to be developed for specific industries and applications.
Achieving faster screening speeds
Over the years, various designs of industrial sieves have been developed for separating materials. One design incorporates a vibratory motor mounted on spring suspension. Because this design is quite simple to manufacture, it is one of the most commonly available type of separators. An alternative is to employ a standard drive motor, with a separate vibrator housing mounted on a rubber suspension. Examples of such machines are the Finex SeparatorTM and Finex 22TM.
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 2800rpm 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” industrial sieve operating at 2800rpm can significantly out-perform a 48” diameter machine operating at 1400rpm on materials which are traditionally difficult to screen.
Seeking smaller footprints
One of the biggest developments in sieving technology minimised space usage to allow sieving machines to fit into process lines more easily. While most major handlers of bulk powders realise sieving is an important step in their process, there remains concern about the availability of floor space for this function.
Suppliers have therefore strived to produce smaller units that can still meet demanding throughput requirements. An example of such a machine is the Russell Compact Sieve®, which is a low-level machine that offers the same if not better performance as standard sized machines.
These compact industrial sieves are now one of the most widely used screening solutions across numerous bulk material handling applications. Companies appreciate having units with a small footprint as space requirements are often limited, but capacity levels must remain high to ensure there are not bottlenecks in the process which would compromise profitability.
Russell Finex Ltd
Tel: +44 (0) 20 8818 2000