Fresco Systems Australasia have extended their range of rotary sifters with the release of an enhanced in-line version. Typically, rotary sifters are gravity feed with a controlled feed or are fitted with a cyclone and rotary valve on the infeed and another rotary valve on the discharge.
This increases capital and operational costs and requires a larger area for installation. Fresco Systems Australasia in-line rotary sifters are designed to operate as an integral part of the pneumatic conveying system. These can be installed directly into the pneumatic conveying line irrespective of whether it is a vacuum or pressure system.
Rotary sifters are commonly used for classifying, grading, de-lumping and screening foreign matter such as fragments of packaging materials and insects, which inadvertently enter the process. Fresco Systems Australasia’s in-line rotary sifters work on the principle of product entering the rotary sifter through the pneumatic conveying line and are then fed into the sifting zone by means of an internal screw auger. In the sifting zone, the material passes along a cylindrical screen aided by five rotating single row brushes or beaters, which sweep the material through the screen.
The material is separated into thrus and overs with the particle size separation depending on the aperture of the screen. Particles too large to pass through the screen (called overs) pass along the screen until they are rejected into the sealed overs container. Particles passing through the screen are generally the desired product and continue into the downstream process through the pneumatic conveying line.
Installed directly into pneumatic conveying lines the in-line rotary sifters can operate between -50 and +80kpa. This covers most standard lean phase pneumatic conveying systems. Screens manufactured from punched plate or woven wire with apertures ranging from 250micron to 10,000micron are used. Designed for single particle size separation, the screen is fitted to a support frame that is accessed through the swing end door.
The screen can be visually inspected by the operator quickly without the use of tools. This operation ensures that the product entering the process is not compromised by a hole in the screen. O-ring seals on the access door ensure a dust tight operation when under positive pressure.
Fresco Systems Australasia’s in-line rotary sifters are available in four sizes and differing materials of construction and finishes to suit the customer’s application. All models are fitted with Fresco Systems Australasia’s lip seal and interlocking drive arrangement. The internal rotor is dynamically balanced and the end bearing mounts are laser aligned providing a smooth operation.
The screw and brush sections are easily removed leaving the stub shafts secured in the twin bearing mounts and shaft seals. This reduces the damage on shaft seals caused by the operator’s error. In-line rotary sifters are suitable for a range of products from fine powders to coarse granules and beads.