Abstract: The invention relates to a method for treating plastic material, especially polyethylene terephthalate, wherein the relatively low temperature material is initially crystallized by heating before subjecting said material to heating or condensation in the solid phase. The material is then exposed to a hot treatment gas for at least 10 minutes in at least two chambers (2) of an apparatus and crystallized at a temperature above 135° C., e.g. 140-180° C. The is subsequently heated in a preheating chamber (3) having at least one to eight stages at a temperature of at least 185° C., preferably at least 200° C. and more preferably around 220° C.

Abstract: 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 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.

Abstract: The invention relates to a method for treating plastic material, especially polyethylene terephthalate, wherein the relatively low temperature material is initially crystallized by heating before subjecting said material to heating or condensation in the solid phase. The material is then exposed to a hot treatment gas for at least 10 minutes in at least two chambers (2) of an apparatus and crystallized at a temperature above 135° C., e.g. 140-180° C. The is subsequently heated in a preheating chamber (3) having at least one to eight stages at a temperature of at least 185° C., preferably at least 200° C. and more preferably around 220° C.

Abstract: The invention relates to a drier-heat-exchanger for heat treating PET granulate and similar products. The drier has a channel which is delimited by air permeable sheets. This ensures that the product can pass through efficiently and evenly which in turn means that a higher gas speed can be used without the product being stirred up and therefore shorter heating times are possible.