Drying: Compressed Air Dryers Reuse Process Air to Boost Efficiency
Compressed air dryers capture dry blower air from extrusion blow molding process for greater efficiency.
FarragTech will feature its CARD (compressed air resin dryer) technology at K 2019, displaying three bulk material dryers, as well as two internal blow molding cooling units. The CARD E/S, CARD M and CARD L/XL dryers and Blow Molding Booster and Blow Air Chiller internal cooling units will be presented during the show. (Note: Farragtech became part of Wittmann Group in early 2020.)
FarragTech’s CARD dryer can be combined with systems for condensation water protection and for internal mold cooling.
The company noted that traditionally in the extrusion blow molding process, it was standard to vent the dry blower air at the end of each cycle. Seeing this as wasteful, Rainer Farrag, founder of the FarragTech GmbH developed CARD technology in 1991 to use the air for resin drying. Since that time, FarragTech says it has made improvements, including better process integration and new controls, including a sleep mode. With that the amount of air is reduced after reaching a set temperature in the upper range of the drying hopper. In addition, heat recovery from the air compressor has further boosted efficiency.
FarragTech notes it has combined the dehumidification of the resin with the internal cooling of the product, avoiding material stress due to the additional condensation water of the supplied exhaust air. As a result, it says production could be increased by 35% with greater quality and lower costs.
Drying is complicated.
Whether you’re blow molding PET bottles or extruding APET sheet, you’ll produce amorphous scrap in the process. How you handle it will impact your production costs. Re-crystallizing it will help.
The reason you dry certain plastics is to get the moisture out. But why does the moisture have to be taken out before processing?