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AssigneeAkzona Incorporated
InventorsHarley Kilsdonk, Frits Linde, Petrus L. Schippers
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A device for filtering a liquid, particularly molten polymer, removes incompletely molten polymer, foreign matter, aggregates of various additives and the like from the molten polymer prior to further processing of the liquid such as extrusion through a spinneret plate. The device comprises a housing provided with a liquid inlet and a liquid outlet and, positioned between the inlet and the outlet, a filter pack built up of a number of filtering disks and supporting disks. The disks are so arranged the liquid to be filtered is caused to flow between a center portion and an outer surface of the filter pack. On the filter pack there is placed a piston for applying a compressive pressure to the pack. The piston is displaced and acts to compress the filter pack on a liquid supply side under the influence of the pressure of the liquid to be filtered. In the device between a zone upstream and a zone downstream of the piston there is formed a liquid passage that provides a pressure drop in the liquid of at least 25 kPa.
A device for filtering a liquid, which comprises a housing provided with a liquid inlet and a liquid outlet and, positioned between said inlet and said outlet, a filter pack built up of a plurality of filtering disks and supporting disks, means including said disks for causing the liquid to be filtered to flow between a center portion and an outer surface of the filter pack, said device being characterized in that on the filter pack there is placed means for applying a compressive pressure to said pack, said pressure applying means including a piston which is displaced to compress the filter pack on a liquid supply side as a result of a pressure drop of at least 25 kPa in the pressure of the liquid to be filtered, and in that between a zone upstream and a zone downstream of the piston there is formed a liquid passage means for providing a pressure drop in the liquid of at least 25 kPa.
A method of filtering polymeric-containing liquids having a viscosity higher than 10 Pascal seconds in a filtering device having a housing provided with a liquid inlet and a liquid outlet and a filter pack positioned between said inlet and outlet, said filter pack being formed of a plurality of filtering disks and supporting disks arranged to allow for flow of liquid to be filtered through said pack and means for applying a compressive pressure to said pack which includes a piston displaceable to compress the filter pack as a result of a pressure drop of at least 25 kPa in the pressure of the fluid to be filtered, which comprises introducing the liquid to be filtered into said filtering device via said liquid inlet, applying liquid pressure to said piston to compress the plurality of filter disks and supporting disks and simultaneously introducing the liquid to be filtered into said filter pack disks via a liquid passage means that is formed between a zone upstream and a zone downstream of said piston,, said liquid passage means providing a pressure drop of at least 25 kPa and thereafter passing the liquid through said filter pack and to said liquid outlet.
Dependencies are inferred from the claim text.