PROCESSING | MELT FILTERS
State-of-the-art For its laser filters Erema uses a special hard steel plate in which the filtration holes are manufactured, as the name implies, using a laser. As holes get blocked by contaminants, a scraper movement is actuated to free them. Each screen has three scrapers, and wiping occurs on a virtually continuous basis. According to Obermayr,
this ensures a high proportion of
Above: The SW RTF filter from Erema’s Powerfil division is a partial surface backflush design
open area, which enables a high throughput even with very contaminated materials. Laser filters are known to provide continuous
Right: Erema says that its Laserfilter gives continu- ous filtration at stable pressure
filtration at very stable pressure levels and are capable of supporting uninterrupted periods of operation lasting many days or even weeks. They also provide a very short residence time of con- taminants on the filter media com- pared to mesh screen filters, where the particles will not be removed until the next periodic backflush. “The filtration fineness can go as low as 70 microns, although in many cases a direct comparison of mesh filters and laser filters shows that the laser filter screen provides a better-defined hole- geometry which ensures a better classification efficiency,” said Obermayr. Erema melt filtration systems
feature screens with large surface areas to prevent pressure spikes. “The filters are easily accessible so that they can be reached quickly, and our
MELT FILTERS | PROCESSING
intuitive HMI helps the operator to interact with the system,” Obermayr said. “Any wear components in the system are easily accessible to minimise down time and eliminate complex training requirements for operators.”
PCR processing
At Italian machinery manufacturer Fimic, sales director Erica Canaia also points to increasing requirements for processing PCR. “The post-con- sumer recycling market is improving and increas- ing worldwide,” she said. “Better technology is required for high-end recycling applications and filtration is a critical step to obtain high-quality pellets from post-consumer waste.” Canaia points out that PCR melt streams can
IMAGE: EREMA
differ significantly depending on the material’s origin, sorting, and pre-treatment. Prime customer considerations include increased throughput capabilities and reductions in operating costs. “Melt filters need to be automatic and able to reprocess contaminated materials on a continuous basis,” Canaia said. “They must be simple to use and to maintain, as well as efficient. After China’s ‘green fence’ was created, we saw higher levels of plastics waste worldwide with more aggressive contamination, which conventional technolo- gies were not able to handle.”
Taking on PVC One of the latest developments at Fimic is a filtration technology applicable to recycling of flexible and rigid PVC. “This is a breakthrough, because until now no continu- ous scraping technology could be applied to recycle PVC waste constantly,” said Canaia.
IMAGE: EREMA
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