improvement in blood filtration devices in the techniques of extra corporeal circulation

摘要

1334555 Filters for human blood PALL CORP 9 Nov 1971 [10 Nov 1970] 51898/71 Heading B1D A filter sheet, suitable for use in the removal of microemboli from human blood, is woven in square weave from polyester monofilaments so that the pore size is in the range 25-50 microns and the open area is in the range 25-40%, the filaments being attached together, e.g. by sinter-bonding, at their crossing- points. The monofilaments may be made from polymers of ethylene glycol and terephthalic acid, or of other glycols and dicarboxylic acids. The filaments have a diameter in the range 25-50 microns. In the filter unit shown, the filter sheet 6 has been sandwiched between two sheets 11, 12 of polypropylene netting, and the composite has been corrugated and formed into a cylinder around a rigid perforated polypropylene core 14, the ends of the cylinder being fused to polypropylene caps 7, 8. The polypropylene housing comprises two portions 16, 17 bonded together, each having a connection 20, 21 to a blood circulation system. When the unit is first put onstream, air is expelled from the interior through vent 30. The flow of blood can be in either direction through the unit. Other plastics material may be used instead of polypropylene, e.g. polyamides, polyvinylidene chloride, polycarbonates, polytetrafluoroethylene and polytrifluorochloroethylene. A filter unit is described which has a housing in the form of a flat pouch, the rigid core being dispensed with (Figs. 5 to 7, not shown).