Using proprietary equipment and processes which combines a ‘slit and stretch’ function, Dexmet performs an expansion procedure on the polymer to produce a diamond configured, open area mesh product for filtration applications.
Aptiv film was reportedly selected for its superior combination of mechanical strength, chemical and high temperature resistance. “While it technically falls under our high temperature PolyGrid product line,” said Ken Burtt, VP of sales and marketing at Dexmet, “APTIV film provides much more than just high temperature capabilities. It also has great chemical compatibility as well as mechanical strength that may be required for certain filter applications in harsh environments making it more of a ‘high performance’ PolyGrid material.”
Expanded mesh products are used in applications requiring membrane support, purification, and separation. For applications requiring high temperatures to filter caustic gases or fluids, such as the semiconductor, chemical processing, and petroleum/gas industries, the filtration media typically being utilised is polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), and ethylene chlorotrifluoroethylene (ECTFE). “Although PTFE, PFA and ECTFE have good heat and chemical compatibilities, they lack mechanical strength,” said Burtt. “As filter performance demands increase, with higher pressures, temperatures, and aggressive environments, there is a need for better performing material, such as Victrex PEEK polymer.” The Aptiv PEEK films include low outgassing and extractables as well as low moisture absorption.
The advantage of an expanded product, especially important in a filter design, is that the material is one homogenous unit - the strands do not move relative to the other strands so opening sizes don’t change. Another advantage is the geometry of the opening the expanded process produces. The material has a three dimensional geometry which allows for multiple flow directions, improving cross flow while reducing pressure drop.