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Orthos offers hygienic design screening machines

Edited by the Processingtalk editorial team Dec 23, 2008

Orthos introduces the Allgaier Process Technology hygienic-design circular tumbler and vibratory screening machines.

The machines conform to all FDA and GMP (Good Manufacturing Practice) criteria relevant to the pharmaceutical, fine chemical and food processing industries.

TSM-type Allgaier hygienic tumbler screen

ATEX-certified versions are also available.

Allgaier circular screens comprise of the Vibrall simple twin-vibrator motor circular screen; the VTS vibratory tumbler screen; and the TSM/tsi tumbler screens.

If the process demands a higher specification, for instance gas-tight construction, the screen frames are machined and fitted on both sides with an O-ring seal.

Robust, quick-release clamps compress together and secure the sections to form the screen-casing.

If quick access to the screen panels is required, the machines can be equipped with a hinged top-cover, secured by a quick-release closure mechanism.

The machines can be fitted with a WIP (Wash-in-Place) spray system, which cleans all inner surfaces.

Vibrall machines perform a vertical vibratory motion and are designed for easy screening duties.

Eleven models with either one or two decks in the 500 - 1200mm diameter range are available.

Ball-deck mesh cleaning is optional.

The VTS-type screen is powered by a single flange-mounted vibrator motor and is suitable for simple applications.

It is also suitable for wet screening and has, for example, been successfully used for screening liquid chocolate.

Options include ball-deck and ultra-sound mesh cleaning.

Five models in one-, two- and three-deck versions with diameters in the 600 - 1400mm range are available.

The Type TSM/tsi tumbler-screening machine contains a standard foot-mounted motor, which operates an eccentric shaft mechanism that drives the Type TSM/tsi.

The speed of the motor, the shaft eccentricity and the degrees of radial and tangential inclination are all variable within fixed limits.

This Multibalance drive neutralise 96 to 97 per cent of all dynamic forces generated by a machine.

It is adjustable to match any changes that affect a machine's weight.

The machines can be equipped with up to five decks.

Material is fed centrally onto the top deck and moves in a spiral towards the product outlet.

This spiral provides a long screening path, making it suitable for fine screening.

The length of the path and therefore the residence time are determined by the adjustments mentioned above: these are easily recorded and reproducible.

Options include ball deck and ultra-sound mesh cleaning.

The range comprises eleven models with diameters varying from 600 to 2900mm.

Mechanical and hydraulic lifting equipment is available for use with the larger and heavier models to help with dismantling the machines for maintenance.

The larger mesh panels are available in segmented form to make mesh-handling easier.

Ball decks are not universally appropriate as they can cause product contamination and mesh damage, particularly when fine aperture meshes are involved.

They free particles lodged in the mesh apertures but don't break up the agglomerates formed as a result of inter-particle surface forces in the case of ultra-fine screening.

The screening of ultra-fine materials poses additional problems, because the free aperture area of fine meshes is a relatively low proportion of the whole mesh area: surface forces cause powder particles to form agglomerates, which bridge over the mesh apertures and coat the mesh wires, reducing the already restricted free-mesh area.

The results are a low throughput rate, a high degree of contamination of the coarser fractions with fine material and inefficient product recovery.

Ultra-sound alleviates this by applying particle accelerations of up to 15000G to effectively break up the agglomerates and free the mesh surfaces of adhering particles.

None of the components in Allgaier's ultra-sound system heats up, even during prolonged continuous use.