A dual-lumen catheter comprises an elongated cylindrical tube made of silicone and having an internal septum extending along the length thereof to form a pair of longitudinal lumens. A hollow conical tip is formed on the distal end of the tube with the outside surface of the conical tip merging smoothly...http://www.google.de/patents/US5221255?utm_source=gb-gplus-sharePatent US5221255 - Reinforced multiple lumen catheter
