Applications for Erema filter systems
- Discontinuous filtration
Discontinuous melt filters which interrupt the melt stream during screen changes are mainly used for applications with a low level of contamination. These systems are suitable for extruders that are easy to start up after each screen change, or where regular short interruptions to production are necessary anyway (e.g. for pellitiser knife changes) and long screen changing intervals are normal. - Continuous filtration with partial area backflushing technology
Continuous Erema filter systems with fully automatic partial area backflushing are recommended for applications with higher levels of contamination or complicated start-up procedures. The fully-automatic cleaning mechanism greatly reduces operator involvement and prevents downtime and time consuming start-ups. They also boost cost-effectiveness by allowing higher proportions of recycled material to be processed without compromising the quality of the final product. An additional advantage is the comparatively large active area of the Erema RTF-type filters which can even prevent peaks in contamination from interrupting the process. Due to the gentle filtration with low viscosities and consequently low shearing of the melt at the screens, resulting from the large total active screen area of the Erema RTF-filters, also gels (depending on application), besides solid contamination, can be held back.
Which filter system for which application?
The diagram shows schematically applications for different conventional filter systems being available on the market with reference to the two main parameters process constancy (system ability to maintain pressure constant filtration) and filtration capacity of system (capability to deal with contamination in the melt).
Optional technologies for optimising the cost-effectiveness of Erema backflush screen changer systems
Erema backflush filter with "VC" (Valve Controlled) technology. The new Erema technology for a drastic reduction of melt losses during backflushing.
Available as an option, the latest developments to proven Erema RTF systems feature a modification that dramatically reduces melt losses during backflushing. This has been made possible by an extreme shortening of the backflushing ways (channels and cavities) plus using new technologies to clean only a fraction of a screen at a time, when applying backflushing. This results in a previously unattainable level of screen cleaning and extraordinary small, economical usage of melt needed to backflush the screen. Details available on request.
These new technologies are especially useful in the filtration of heavily contaminated melts, allowing up to tens of thousands of euros in reduced melt losses to be saved every year.
