PSI-Polymer Systems Inc. (Conover, NC) has been awarded a U.S. patent for a seal technology that prevents leakage in screen changers. U.S. Patent 9,309,974 B1, dated April 12, 2016, was issued to the company for “Seals for use with Low to Medium Viscosity Fluids and Related Methods, Apparatuses and Systems.”
Material leakage on bolt-type continuous screen changers can occur when the viscosity of the process material is not sufficient to create a seal in the close-tolerance gaps between the screen changer and cross bolt(s). Materials that fall into these categories include hot melt adhesives, high MFI polypropylene and others where the melt can readily pass through tight clearances. This patented technology will be used by the company on its CSC (continuous bolt) and DSC (discontinuous bolt) line of screen changers to prevent leakage of high MFI/low viscosity materials being filtered through the equipment.
The novel design has sealed against materials possessing a viscosity as low as 1 centipoise. This impressive feat is achieved by marrying PSI’s close-gap technology with a proprietary ‘U-Seal’ that holds its sealing properties without tearing or shifting.
“We’re excited to be awarded this new patent and to recognize our engineers who have invented a seal technology that truly prevents leakage for difficult-to-seal materials and holds up under real-world operating conditions,” said Don Macnamara, General Manager of PSI-Polymer Systems. “Material leaks for adhesives and low-viscosity polymers are the number one problem processors have when using screen changers for these applications. PSI’s new seal design offers our customers the assurance that their screen changer will perform as advertised without creating undue housekeeping and related safety issues.”
PSI-Polymer Systems is a supplier of polymer filtration equipment, gear pumps, static mixers, divert valves, die changers, custom auxiliaries and engineered system solutions for the plastics extrusion, polymer processing, recycling, hot melt adhesive and food and chemical industries.