The machine consists of a loading hopper which feeds in the raw material and a dosing system with scale, which allows the amount of material fed into the expansion chamber to be accurately weighed. The raw material is fed in quickly by a screw.
The expansion chamber is made of AISI 304 stainless steel and has a specific shape: a cylindrical upper part and a conical lower section.
This shape allows for progressive expansion of the beads and helps to achieve a uniform density.
The chamber houses a mixer shaft, also made of AISI 304 stainless steel, driven by an electronic speed control system.
The rotation speed can be optimized to suit the cycle stage, the type of raw material and the expansion conditions.
An automatic density control device monitors each expansion cycle, thereby ensuring the repeatability and stability of the production process.
After leaving the chamber, the expanded material is conveyed to a fluidized-bed dryer made of stainless steel and equipped with a steam-air heat exchanger, designed to prevent the beads from sustaining damage due to thermal shock.
The beads are transferred to the ageing silos by rotary valve fan.
The system includes a second expansion stage, which serves to control density and ensure process stability.
The Pre-expander is controlled by a Siemens PLC.
The human-machine interface consists of a touchscreen panel, which allows all operating parameters to be selected and stored.
The air and steam inlets are automatically regulated as to volume and temperature throughout all the expansion stages.
The machine is designed to facilitate routine and supplementary maintenance, since it allows ease of access to components for quick replacement of parts subject to wear.
