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  • Publicado : 27 de noviembre de 2011
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Banana Screens

There is no equivalent

Banana Concept
Concept A major innovation in screening technology was the development of the ‘Banana’ multi slope concept screening machine capable of achieving exceptional throughput per screening area. The screening concept is that of a high capacity, thin layer and high velocity machine. The screen includes any number of inclinations from two to asmany as six varying from 45° through to horizontal on the last slope. The various slopes may incorporate deck media with different apertures to meet the particular process requirements. The screens are commonly designed to fit modular polyurethane deck panels. However, woven wire or punch plate may be used. Facilities may be incorporated to assist in the fitting of dust suppression covers. Morerecently the banana screens in double deck execution have been developed again in an effort to reduce the number of equivalent horizontal double deck units installed. Banana screens vary in size from as small as 1.8m wide to as much as 5.5m wide with masses of up to 28 tons. The more common sizes are 3.0m wide by 10m long with a mass of approximately 16 tons.

Characteristic material flow overMulti Slop Banana Screen Benefits Improved sizing efficiency due to thin layer screening Low water consumption when wet screening Low energy requirement High specific feed rate and capacity resulting in reduced screen (unit) size.


Quality by design
Suspension Suspension is either by means of steel coil springs or moulded rubber buffers. Buffers have higher dynamic loads but are moresuited to wet applications. The number and type of buffers or springs is determined by the mass of the screen. Vibrating Mechanism Screens are vibrated in linear motion using geared exciters with contra-rotating out-of-balance masses. Different sizes of exciter units or multiples thereof are used for the various models of screen depending on the screen mass. The advantage of the geared exciter is thecontinuous splash oil lubrication, which ensures long life. Exciters are driven externally using cardan shafts via v-belt and pullers, for optimal performance. Line of action varies from 40° through to 65°, most common being 45° or 50°.

Drive Drive transmission is through cardan shaft, pulleys and v-belts allowing simple adjustment of screen operating frequency.

Subframe Vibration absorbingsubframes are used to reduce the dynamic loads imposed on the support structure. This is normally in case of screens situated ‘high-up’ in screening buildings.

Construction The screen frame is bolted construction by means of high tensile ‘Huck’ or threaded fasteners. Minimal welding is used but only in low stress areas. All joints incorporate an epoxy adhesive between the mating faces toeliminate the ingress of moisture and thus prevent deterioration of the integrity of the joint through corrosion. The epoxy also assists in strengthening the joint.

Surface Protection High quality preparation and corrosion protection systems ensure a good corrosion protection resulting in improve screen life.

Deck Support Stringers and Beams The use of stringers and beams as a deck support systemnot only gives longer life due to comprehension rubber protection but also allows for the renewal of only those members that require replacement.

Sceen Deck Most often the deck support structure is designed for the use of easily removable polyurethane foot modular panels. Other types of screen media may be used including woven wire and punched plate.


Technical Support
Screencapacities vary widely depending on the material characteristics and the separation required. The Process and Application Engineers at Linatex utilise not only their many years of developing local applications but also the experience of worldwide installations to ensure that they optimise the best screen requirements available. The following data should be made accessible to facilitate the sizing...