PRE-EXPANDERS
VPX BATCH PREEXPANDER
Pre-expansion is one of the five essential stages in the expanded polystyrene (EPS) production process. During this phase, raw polystyrene granules are transformed into high-quality EPS. By exposing the raw granules directly to steam, they expand into larger EPS beads characterized by a non-interconnecting, closed-cell structure.
- Raw material auger feed screw
- Raw material loading and storage station
- Conical foaming vessel with wedge-wire base
- Fast material discharge through bottom butterfly door
- Frequency-controlled agitator speed
- Vibrating sensors for detecting grey material
- Fluidized bed with Z-segment drying floor
- Lump crusher to prevent material blockages in the pipes
- Digitally controlled steam and air regulation valves
- Automatic density control unit
- Electronic weighing system
BUTTERFLY DOOR
- Butterfly doors to empty the vessel in the shortest possible time
- Larger opening diameter compared to traditional systems
- Easy access for maintenance
ADVANTAGES
- High-quality bead expansion
- Wedge-wire screens for uniform steam distribution
- Tolerance within ±1% through continuous monitoring
- Consistent density distribution across each batch
- Precise target density repeatability
- Shorter cycle times compared to traditional systems
- Optimized raw material utilization
- Enlarged discharge opening compared to conventional systems
- Easy maintenance access
- Reduced energy consumption with unique steam and vapor
PREEXPANDER TYPE
| Parameter | VPX-1500 | VPX-3500 | VPX-5500 | VPX-7500 |
| Usable volume | 1.5 m³ | 3.5 m³ | 5.5 m³ | 7.5 m³ |
| Steam plate | 800 mm | 1.200 mm | 1.200 mm | 1.200 mm |
CAPACITY AT DENSITY
| Density (g/l) | VPX-1500 (kg/h) | VPX-3500 (kg/h) | VPX-5500 (kg/h) | VPX-7500 (kg/h) |
| 12.0 – 12.5 | 650 – 775 | 1.300 – 1.550 | 2.210 – 2.635 | 2.990 – 3.565 |
| 14.0 – 16.0 | 825 – 1.000 | 1.650 – 2.000 | 2.805 – 3.400 | 3.795 – 4.600 |
| 18.0 – 21.0 | 1.000 – 1.150 | 2.000 – 2.300 | 3.400 – 3.910 | 4.600 – 5.290 |
| 22.0 – 25.0 | 1.375 – 1.600 | 2.750 – 3.200 | 4.675 – 5.440 | 6.325 – 7.360 |
OPTIONS
- Multi-Pass second expansion Unit VMP
- Continuous Preexpander for second pass – CANNON
- High Density Unit VHD
- Energy Recuperation System by connecting to vacuum system
CONTINUOUSLY OPERATED PREEXPANDER TYPE CANNON
Instead of blocking the VPX batch pre-expander by using it in multiple stages to obtain lower densities, the continuously operated CANNON pre-expander can be used as a second-stage expander. The price difference between a continuous pre-expander and an MPU (multiple stage unit) is small, while the overall capacity of the pre-expansion plant is significantly higher when using both systems at the same time.
