Over the years, a few basic designs of vibratory sieves for grading materials have been developed. One design incorporates a vibratory motor with integral bearings and out of balance weights mounted in a fabricated base. The base is static and the vibrating part of the machine sits on a spring suspension. The Russell Eco Separator™ is a good example of this design. This is one of the most common separators available on the market mainly because this design is quite simple to manufacture.
An alternative is to employ a standard drive motor (i.e. not vibratory) with a separate vibrator housing mounted on a rubber suspension. Examples of such machines are the Finex Separator™ and Finex 22™ from Russell Finex. Most machines vibrate at 1400 rpm, but by separating the motor from drive bearings and out of balance weight system the rubber suspension in this type of design operating speeds can be increased up to 2800 rpm.
Rubber suspension achieves:
- Higher capacity
- Greater sieving accuracy
- Lower noise
This has 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. This development has been utilized extensively throughout a diverse range of industries but one very common application is the screening of high viscous liquid paints.
As well as increased efficiency and performance, another key benefit is that Rubber suspension makes sieves far quieter in operation when compared to sieves fitted with springs. As well as adopting rubber within the vibratory suspension system, fitting rubber feet on the base also contributes to a low noise level, compared to other machines where metal in direct contact with the floor may set up adverse vibrations.