Densifiers are used to compact loose foam products into dense blocks for transportation or storage prior to recycling. While traditional balers can be used to compact the foam, they do not work very well. A 48-foot truckload of baled foam weighs only around 16,000 pounds, whereas a truckload of densified foam weighs 40,000 pounds. New densifiers cost as little as $18,000.
Four commonly used densifiers are hydraulic, thermal, screw drive, and a hybrid.
Hydraulic densifiers use hydraulic pressure to compact the foam and eliminate its memory. With a continuous operation model, the foam is extruded into a dense log. Hydraulic densifiers do not use heat to compact the foam and produce no smoke or odors. They can effectively process various densities of foam at the same time without melting in the machine. Since city foam recycling programs receive a mixed stream of foam materials, this feature makes hydraulic densifiers ideal.
Thermal densifiers use heat to melt foam into a taffy-like state. The foam is extruded in the form of a rope and then transferred to containers. Additional labor is required to mold the foam into a shape that can be stacked on a pallet. Thermal densifiers work well with mixed densities and produce “ingots” that can be stored outside in rain and wind. While these machines do a great job compacting foam, they are known to produce unpleasant odors and require more electricity to operate.
Screw Drive Densifier
Screw drive densifiers use augers to push foam through a chamber at a specific speed and pressure to densify the foam into a solid log or block. The material is compacted by pressure, not heat. They perform best when the feed stock is limited to one density of foam at a time, however, some companies claim to have made technological breakthroughs that allow their equipment to process mixed densities of foam well. To be safe, it is always best to run a trial prior to purchasing equipment.
Hybrid foam densifiers combine the best features of the screw drive densifier system with those of the hydraulic densifier system, resulting in an efficient way to process recycled foam #6. Hybrid cold compaction densifiers use augers and hydraulics to compact foam with no melting. Some advantages of hybrid densifiers include tidy output, a small footprint, and highly effective and controllable output density.
Grinders are used to break up large pieces of foam #6, such as solid packaging materials, before densification. Some cities and municipalities choose to purchase a grinder and densifier in one, like the system offered by Demand Products.
Manufacturers of foam #6 recycling equipment include Matrix Manufacturing, Sebright Products, Inc., Foam Equipment & Consulting Co, EnStyro, and Avangard Innovative.
Based in Ogden, Utah, Matrix Manufacturing distributes the Polymax polystyrene densification system to cities, waste services and foam producers nationwide.
Sebright Products, Inc.
Sebright Products, Inc., based in Hopkins, Michigan, sells waste handling and recycling equipment including densifiers, extruders and conveyors.
Foam Equipment & Consulting Co.
Foam Equipment & Consulting Co., based in St. Louis, Missouri, sells compactors and densifiers for foam recycling as well as shape molding equipment for expandable bead foams.
EnStyro produces shredding equipment for expanded polystyrene foam.
Avangard Innovative, headquartered in Houston, Texas, partners with companies to maximize their recycling and overall sustainability efforts.
Located on Ontario, California, INTCO Recycling manufactures and sells GREENMAX densifiers (Compactors & Melters). INTCO also purchases back densified foam #6 and reuses it to make picture frames products.