PSI-Polymer Systems, Inc. Continuous Backflush Screen Changer is Specially Designed for Extrusion & Pelletizing of Recycled Materials Hickory, NC (October 30, 2008)
Extruders and pelletizers running recycled materials can greatly benefit from the use of the continuous backflush screen changer (CSC/BF) from PSI-Polymer Systems Inc. The CSC/BF provides maximum melt filtration capabilities, separating the impurities out of the material and allowing processors to continue running with no downtime.
Because of the unique design of the CSC/BF, it provides as much as 25x the life span of the screen pack filters compared to standard styles of screen changers. This allows processors to confidently process recycled materials without fear of clogging the system.
“We have seen a continued trend towards more use of recycled materials,” said Rob Martin, General Manager of PSI-Polymer Systems Inc. “These materials typically contain a lot of impurities that need to be filtered out of the melt stream. The CSC/BF is the ideal product to give processors peace of mind that they won’t need to shut down their extruders or pelletizers due to clogged screen packs.”
A standard screen changer on an extruder can clog quickly, said Martin, and the dirtier the material, the faster the screen changer can clog. “We have seen situations where a standard screen pack needs to be changed many times an hour,” he said. “This obviously causes the processor an unacceptable amount of downtime.”
With the continuous backflush technology of the CSC/BF screen changer, the material being processed is divided into two melt streams each with two filtration cavities. When upstream pressure rises due to a high contaminant level, PSI’s Extrudepak PLC control automatically actuates each piston to its backflush position, allowing pressure to push contaminants off the dirty screen pack. The contaminants are purged out of ports in the housing, and the purged/cleaned screens are returned to their original position until the backflush cycle takes place again.
“Because of this technology, processors who typically would purchase class ‘A’ recycled material can actually use class ‘B’ or ‘C’ materials,” said Martin. “This allows them to save substantially on the cost of materials.”
The CSC/BF features guaranteed leak-proof operation to 10,000 psi and operates with process temperatures to 700°F. Because there are no seals or contact parts, PSI provides a five-year warranty against melt leaks. They are available in sizes ranging from a screen diameter of 4.58” (116mm) to 9.07” (230mm). Like all PSI products, the CSC/BF is proudly manufactured at the company’s USA headquarters