The EPS raw material is conveyed as granules to the preexpander, where it is heated by means of wet steam. The hot steam softens the polystyrene beads and activates the blowing agent dissolved in them. This evaporates and causes the softened beads to expand. The bulk density can be adjusted by the weight of the raw material and the foamed volume. The EPS beads pre-expanded in this way are then cooled and stabilized in a fluidized bed on an air cushion before being conveyed by blower via a rotary feeder into the silos.
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Welding of the end products: During the subsequent intermediate storage, the blowing gas diffuses out of the pre-expanded polystyrene beads and air penetrates. This "packed air" is further processed in the converting process on an automatic moulding machine or in a block mould. To achieve low bulk densities, EPS can also be post-foamed in a second pass. For expandable polypropylene (EPP), EPP/HP pre-expanders are available for lightweight foaming.
Contact us to discuss your requirements of drying area. Our experienced sales team can help you identify the options that best suit your needs.
EPS Pre Expander Machine is widely used for high density and middium capacity of EPS foam beads production line.
1. Fully automatic production.
2. Controlled by touch screen and PLC, easy to operate.
3. High output and save energy.
4. Exact density of foam beads.
5. Stable quality and less failure.
If you want to learn more, please visit our website lost foam casting products.