BUSS optimises COMPEO series for compounding plasticised PVC

BUSS AG’s modular COMPEO plasticised PVC compounding systems are now available in a cascade configuration for optimum results.

The discharge and pelletising unit is mechanically decoupled from the compounder and fed in free fall via a connecting tube. This arrangement avoids back-pressure build-up at the transition between compounder and discharge unit and prevents the PVC compound from being exposed to excessive temperatures.

This two-stage configuration has been developed with the aim of enhancing ease of use and operator safety since the tube and diverter valve can be operated and cleaned without tools. The single screw discharge unit is arranged at right angles to the compounder, which engineers devised to help keep the overall unit short.

The swivelable, easy access BUSS die-face pelletising unit is equipped with a two-, three-, or four-bladed knife and is likewise mounted on the discharge unit to save space. The adjustable blade drive ensures optimum cutting quality and uniform, cylindrical pellets. A braked motor securely locks the knife drive, so greatly increasing safety for maintenance and cleaning personnel. A sensor on the heated die plate sensor trips an automatic safety shutdown if the maximum permissible pressure is exceeded.

Dino Kudrass, Head of Development and Design, said: “When it comes to compounding plasticised PVC, the decoupled configuration has particular advantages over our usual conical twin-screw discharge unit. It helps to minimise residence times for the thermally sensitive compound in the cylinder and so provides effective protection from degradation. And because the melt can be degassed in the connecting tube, the compounder’s process section can be shortened by the length of a degassing module.”