BigPatents India

The invention relates to a device for the thermal secondary treatment of plastic material in granulate form, in particular of polyester material such as polyethylene-terephthalate, in a flat shaft reactor comprising a substantially rectangular cross-section. The shaft (1) consists of an upper region (4) and a lower region (5), whose horizontal cross-section (Q5) tapers downwards in a vertical direction. At least sections of the vertical shaft walls (4A) and (4B) have screen-type gas dispersion regions. The large opposing shaft walls 5a and 5b of the lower outlet region (5) are likewise gas dispersion regions. The gas dispersion regions consist of wedge-wire screens, which can have different arrangements of gaps according to requirements. The special gap arrangements in the wedge-wire screens allow the standardisation of the granulate speed profile over horizontal cross-sections in the shaft region. Vibrations and impact stresses of the device are reduced by the mounting of elements ("diamonds") and the granulate speed profile is further optimised. Drawing: 4 Sheets Total Pages: 14 Fig. 1