Duckbilled check valves and methods of making and using same
 Disclosed herein are closures that are formed via an injection molding process with a thin breakable web. When they are first placed in a fluid conduit and exposed to line pressure the web will break open so as to thereby create a duckbilled type check valve. Thus, the closure can provide a seal during long-term storage prior to use. However, once used it functions as a check valve. 
S. C. Johnson & Son, Inc.
F F Y Y Y
F16K F16K Y10T Y10T Y10T
inventional inventional additional additional additional
Peter M. Robert W. Cory J.
Neumann Balfanz Nelson