A valve for controlling material flow through a catheter, comprises a first flexible member including a first moveable element, wherein, when the first moveable element is in the open position, material may flow past the first flexible member through a first lumen of the catheter and, when the first...http://www.google.com/patents/US7435236?utm_source=gb-gplus-sharePatent US7435236 - Pressure actuated valve with improved biasing member
