melt filtration | Technology
As well as bumpers, other ELV waste such as PP battery casings can be handled by the ERF filter. These mainly contain contami- nants like paper and metal as well as high viscosity plastics. Ettlinger says ERF filters enable high quality regrind to be manufactured at a rate of up to 3 t/h. Development work by Erema that led
to the launch of its Intarema plastics recycling system included improvements to its melt filtration technology. The Austrian company’s Laserfilter has two major improvements: a new design of the
Above: Erema’s Laserfilter technology
microns), which leads to superior product quality and a lower percentage of melt loss, says Fimic. Ettlinger’s most recent product development is its
ECO continuous melt filter, which was launched in the market in 2014. It is designed to support continuous extrusion processes for film, sheet and semifinished products. ECO works according to the same basic principle as Ettlinger’s ERF technology (see below), and is used to filter both virgin and slightly contami- nated recycled material (up to 1.5% contaminants). The company says that compared with other melt filtration systems, using the ECO filter leads to fewer black specks and inclusions in the film or compound and fewer specks in hygiene films due to gels or agglomerates. Ettlinger’s ERF melt filters are used for recycling a
wide range of plastic materials, for example film and other packaging waste, PS waste from electronics, EPS sheet and more. The company also highlights the use of ERF filters for end-of-life vehicle (ELV) recycling. The sorted flakes from ELV generally also contain significant quantities of paint residues from bumpers and other exterior components as well as elastomer residues – which can account for up to 30% – wood, cellulose and fibres. An ERF filter with a screen size of 80 microns can efficiently remove these unwanted particles allowing the final product to be used in injection moulding of automotive parts, the company says. The central component of the ERF filter technology
is a slowly rotating, cylindrical filter screen which is driven by a servo motor. It has millions of conical holes and can be supplied with a variety of screen sizes. Contaminants are wiped clean from the filter surface after each rotation of the screen, avoiding blockage of the holes. “Thanks to this continuous cleaning principle, a constant pressure is maintained in the system and elastomers – which would otherwise be forced through the screen mesh as more and more pressure builds up – are now reliably removed from the rotating filter drum and discharged from the process,” says Ettlinger.
32 PLASTICS RECYCLING WORLD | June 2017
scraper geometry and a discharge system which removes the filtered contaminants more quickly and thoroughly than before. In the Laserfilter’s set-up, the contaminated plastic
melt is pressed through two laser-bored screen discs in a parallel configuration. A scraper disc rotates between these filter discs. The rotating scraper makes the Laserfilter different from other technologies which have a rotating screen. The static screen is sealed and this prevents any items which are filtered out from getting into the plastic melt. The scraper removes the filtered contaminants from
the screen immediately and conveys them continuously to the discharge system. The contaminants are removed under control and with a minimum of melt via the optimised discharge system. The scraper and discharge screw speeds depend on the pressure and can be controlled fully automatically. Another feature of the Laserfilter is the upstream
distributor ring which acts as a preliminary filter and protects the core components screen, scraper star and discharge system. The Laserfilter is available with capacities of 350 to 3,500 kg/h and filtration of 90 to 800 microns. Erema’s new SW Direct Flow melt filter uses the
company’s established SW filter technology, but in this case it has been reduced to the most important core functions for use with relatively clean applications. Minor contaminants, such as dust, are removed with ultra-fine filter discs below 30 microns, or with standard filter discs from 30 to 90 microns.
Click on the links for more information: ❙
www.nordson.com ❙
www.britas.de ❙
www.cofit.com ❙
www.gneuss.de ❙
www.fimic.it ❙
www.ettlinger.com ❙
www.erema.com
www.plasticsrecyclingworld.com
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