Filtration systems boast resilience
Melt filters get the gunk out of molten resin, but keeping them clean — and running — can be a challenge.
To help with recyclers’ dirty jobs, OEMs continue to improve filtration systems, offering equipment that’s more resilient and easier to use. ADG Solutions, Ettlinger North America and eFactor3 offer some of the latest innovations.
ADG has introduced upgrades to its CFO line of continuous melt filtration systems, as well as a new model that takes over the lead for the best throughputs in the series.
The CFO line is targeted at companies processing contaminated post-consumer and post-industrial PE, PP, PC, ABS and other resins. The systems can handle contamination levels as high as 10 percent for paper and other foreign objects with diameters as large as 0.75 inch.
CFO systems now feature a redesigned, more efficient scraper that reduces the amount of resin that is lost during purging. ADG also has upgraded the controls and computer program so that the operator can vary the number of scrapes between purging cycles for optimal collection of contaminants.
ADG also made the screen plate filter more robust, with more-uniform holes.
Joining the CFO series is ADG’s newest model, the CFO 25, which has a 25-inch-diameter screen. Previously, the screens of the CFO systems were designated in metric measurements; the CFO 25’s screen is about 10 percent larger than the 600mm screen of its predecessor.
With throughputs of as much as 7,500 pounds per hour, the CFO 25 is the most robust of the series; the other melt filtration systems, the CFO 20 and CFO 15, have top hourly throughputs of 1,800 pounds and 4,000 pounds, respectively.
The CFO 25’s flow pattern has been designed so that there are almost no material hang-up points, ADG President Sandy Guthrie said.
ADG also adjusted the plunger and seal in the CFO 25, allowing for easy replacement. Overall, “it has become much more efficient in terms of material loss and purging,” Guthrie said. Also, operators can change screens quickly, in a half hour or less.
ADG designed the CFO 25’s chamber to handle pressures of up to 3,500 psi. The door to the machine has studs all the way around to prevent leaks.
“Once you get a leak in these doors, a polymer with a contaminant that’s an abrasive eventually will wear a path,” he said. “It’s much better from an aspect of someone who’s actually operating the machine, from a point of longevity, from the point of contamination, from the point of not having to clean it up.”
This fall, ADG will begin offering a new diamond-hard plate surface for the CFO line for aggressive and abrasive materials for significantly longer screen life.
Ettlinger recently upgraded its ECO 250 continuous, rigid-screen melt filter for PET, which is targeted at manufacturers of sheet, film, strapping and fiber waste. Improvements include enhanced purge control, a better heat profile and an Industry 4.0 control system, Managing Director Mike Diletti said.
Because the ECO 250 removes virtually all contaminants, manufacturers of recycled PET strapping see dramatically fewer breaks in their end products, saving all the associated hassles of shutting down and restarting production lines, Diletti said. The ECO 250 reduces black specks and provides consistent melt flow with no dead zones. With a filter diameter of about 9.8 inches, the ECO 250 can process about 6,600 pounds per hour.
In July, Ettlinger introduced a 60-micron screen for its ECO 200 and ECO 250 melt filters; previously, the company’s finest filtration screen was 80 microns. The ECO melt filters now have nine filter options with fineness ranging from 60 microns to 1,000 microns. The 60-micron screen is aimed at handling film, sheet and fiber waste.
“We see many projects in PET — that will increase even further with the 60-micron screen,” Diletti said.
Ettlinger said its ECO melt filters require almost no operator intervention and can go months between screen changes. They tolerate as much as 1.5 percent contamination and can even handle gels and elastic particles. Ettlinger boasts of a return on investment of 18 months.
MAS Maschinen und Anlagenbau Schulz GmbH, Pucking, Austria, has debuted the second generation of its CDF 500-D melt filter.
New features include pneumatically actuated scrapers. The pressure of the scrapers against the screen is adjusted automatically by the melt pressure, said Hartmut Bendfeldt, president of eFactor3, which represents MAS in the U.S.
Users can adjust the filter software to automatically increase the rotation speed of the filtering discs and the pressure applied to the scrapers for predetermined periods. This action cleans the filter discs and keeps the scrapers sharp. Dull scraper edges and excessive contaminants trapped inside of the filter decrease the life of the filter discs substantially, the company said.
Scrapers can be changed “in a couple of minutes,” Bendfeldt said. The system also comes with a maintenance-free scraper seal system.
The new-generation system discharges contaminants from the downstream side of the filter, rather than beneath the filter. This permits the use of a larger container for capturing the filter discharge.
As with other MAS continuous melt filters, the CDF 500-D can handle a melt stream with contamination levels of up to 5 percent.
The CDF 500-D uses two filter discs, each 20 inches in diameter, for a total surface area of 566 square inches. It has a capacity of 3,307 to 6,614 pounds per hour. Capacity rates depend on factors such as the amount of contamination in the material and the material type, the company said.
Allan Gerlat, correspondent
ADG Solutions LLC,
Tucker, Ga., 678-292-6144,
Pineville, N.C., 704-944-3232,
Ettlinger North America LP,
Tyrone, Ga., 770-703-8541,