2.9.2.1. Prototype granule expansion. The designed pilot line was
able to produce around 120 port-hole spacers per hour in a semiautomatic
way demonstrating the process feasibility and product
performance. The process consisted of four stages: storage and
dosing unit for granules, microwave system for foaming granules,
extraction stage for removing the product, and conditioning unit
for cooling or heating mould before restarting the process. The
achieved density of the prototype packaging was of 40 kg/m3.