process feature | Screenchangers and melt filtration
Systems. Several safety features have been added, as well as the option for an automatic purge ejector for the back -flushing RSFgenius model. The continuous screenchangers operate automati-
cally, maintaining constant pressure and process conditions. This ensures high product quality and economic efficiency while reducing operator and maintenance demands. Gneuss reports that there is worldwide trend
The AutoScreen Max controls melt pressure at the die
screenchanger, with filter diameters of 325-700mm (12.8 to 27.5in). Multiple screen sizes are available, the largest being 2,000 microns (about 10 mesh). At the other end of the scale, Fimic and ADG now
offer fine filter screens with a size of only 200 microns (about 80 mesh) and expect to make a 150-micron (100-mesh) screen available later this year. “With the ultra-fine filtration provided by the new
screens, users of the Fimic self-cleaning continuous screenchanger can further enhance product quality, a critical requirement for film and other applications requiring a cosmetically desirable appearance and surface feel,” said ADG president Sandy Guthrie. “At the same time, the large surface area of the screen compared to that of other screenchangers facilitates polymer flow and ensures a high level of productivity for the processing line.”
Gneuss has enhanced its melt filtration systems,
including the RSFgenius models
Double advantage The new generation FSC double screenchanger from Maag Filtration Systems is developed for maximum reliability and minimised maintenance costs. Its new sealing system allows it to operate on extrusion lines with high pressures. The design of the internal flow channels and the filtering chamber have also been optimised.
The sealing system, with
interchangeable elements, has been designed so that even the most difficult maintenance can be carried out at the custom- er’s factory – reducing machine downtime. In comparison with the
double-bolt screenchanger, the FSC double flat-slide screenchanger is claimed to allow a quicker screen change. This advantage is because the optimised volume of the filtering chamber minimises the duration of the venting procedure. Gneuss has made further design enhancements to its continuous, fully-automatic Rotary Melt Filtration
36 FILM & SHEET EXTRUSION | December 2012/January 2013
towards bigger extrusion lines and therefore larger filtration systems. It says that the number of RSFgenius and SFXmagnus systems sold in sizes 200, 250, 330 and 400 has doubled in the past 12 months. Recent projects have included melt filtration
systems for the manufacture of foam film and PET film for food packaging, as well as for packaging tapes made from PET bottle flakes. High-Technology Corp has developed a new genera- tion of microprocessor-based controls for its screen- changers. They enable complete integration with the extrusion process including remote start/stop and interlocking features for handling high polymer pres- sures. For the first time, various voltages for the heating elements can be accommodated and the same supply voltage is used for both the process and control zones. These controls provide a comprehensive system that supplies continuous feedback on all the screenchang- er’s operating parameters. These are easily set via a door-mounted display panel. Alarms and indicators immediately alert the user about any system malfunctions and facilitate trouble-shooting by pinpointing the source of any failure. At the same time, safety features prevent the possibility of operating the screenchang- er in an incorrect or unsafe mode. Complete automation of the screenchanger’s functions
enable it to become a fully integrated element in the extrusion process, resulting in
long-term non-stop operation with no process disruptions or operator intervention.
Click on the links for more information: ❙
www.kreyenborg.com
❙
www.psi-polymersystems.com ❙
www.autoscreenchanger.com
❙
www.keyfilters.com
❙
www.fimic.it ❙
www.adgs.net ❙
www.maag.com ❙
www.gneuss.com ❙
www.screenchanger.com
www.filmandsheet.com
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