Duckbill valve and method for making a duckbill valve

摘要

A duckbill valve includes a flexible and hollow body having a first shape upon being formed by injection molding. The body in the first shape has a first opening at a first end and a second opening at a second end. The body is configured to be inverted into a second shape. The second shape has a first opening at a first end and has a slit at a second end. The slit is defined by lips that are pressed together to form a seal.