styrofoam pre-expander

An electronic weighing system measures a precise quantity of EPS raw material per batch-maintaining a weighing deviation within ±0.05 kg-and feeds it into a sealed foaming vessel via a spiral conveying mechanism.

Steam at a pressure of 0.4–0.8 MPa is introduced to heat the vessel to 100–105°C; the blowing agent contained within the beads (typically 5–8% pentane) then vaporizes and expands to achieve the target density.

The fully sealed vessel utilizes a PID closed-loop control system to regulate steam pressure and temperature. With the internal temperature controlled within a tolerance of ±1°C and pressure maintained stably, the beads expand uniformly and achieve consistent density.

Upon completion of the expansion phase, the vacuum drying system activates to reduce the moisture content of the beads to ≤2%, thereby preventing residual moisture from negatively impacting subsequent molding and curing processes.

The foamed beads are automatically discharged and processed through an integrated fluidized drying bed, which performs automatic screening, breaks up any agglomerates, and pneumatically conveys the beads to the curing silos for entry into the next stage of production.