Dryers for glass fibres

Stalam offers a wide range of Radio Frequency equipment specifically designed for the drying of glass fibres in various forms – mainly direct rovings, assembled rovings, yarns and chopped strands.

Precision-wound direct rovings weighing up to 35-40 kg each (approx. 18-22 kg according to industrial standards), placed vertically or horizontally on the RF dryer’s conveyor belt over suitable wooden or composite material holders – designed for the automated handling and transport systems used within the factory – can be dried down to a residual moisture content below 0.1% in a time range of approx. 2 to 4 hours (depending on the winding density and the fibre count) instead of the 20 – 30 hours usually required by conventional hot air circulation ovens. The longitudinal (transverse) expansion of the rovings during the process does not exceed 2-3 mm and there is neither migration towards the roving’s outer layers of the finishing chemicals (resins, starch, lubricants, etc.) nor the surface yellowing effect which is a typical drawback of conventional drying.

The residual moisture content of assembled rovings can be controlled accurately by a suitably adjusted Radio Frequency field, obtaining at the same time the ribbonisation of the fibres.

Chopped strands can be dried quickly and efficiently without any air movement, thus reducing almost completely the dust formation in the production department. Other glass fibre products, mainly in the form of bobbins and packages after various kinds of wet treatments, can be perfectly dried down to the desired final moisture content, efficiently and consistently, without any adverse effect on the finishing chemicals.