Abstract: A PET granule hopper and dryer (1) feeding an extruder (2). The extruder in turn via a rotary seal, feeds a metering wheel (3) on which there are metering devices. An injection-compression wheel (4) supporting injection-compression devices (5) is positioned after the metering wheel (3). If the installation is not designed for continuous feeding of a blower for converting the preformed into packagings, a perform cooler is provided, by means of a cooling wheel (6) equipped with a set of water-cooled devices (1) blowing air onto the performs before they are taken away for storage.