Normally closed duckbill valve assembly

A one-way duckbill check valve assembly for use in a flow path for permitting relatively free flow in said flow path in a first direction from a first to a second end of said valve and for preventing flow in said path in a second opposite direction, said valve comprising:

• a housing;
• a valve body located within said housing and having a central longitudinal axis and an outer wall;
• a pair of valve lips mounted to said valve body within said outer wall and oriented in diverging relationship to each other toward said first end to said valve;
• means forming a pivot connection between said outer wall and said lips;
• means for biasing said outer wall inwardly whereby said pivot connection transmits a force to bias said lips together;
• said valve body and lips being formed of an elastomeric material and wherein said lips define an elongated normally closed outlet opening of said valve at said second end;
• and
• said means forming a pivot connection between said outer wall and said lips including a pair of connecting walls located on either side of said outlet opening and extending radially inwardly from said outer wall to intersect said lips along a smoothly curved edge.

A one-way duckbill valve assembly for use in a flow path for permitting relatively free flow in said flow path in a first direction and for preventing flow in said path in a second, opposite direction, said assembly comprising:

• a housing defining a housing interior having an interior surface and having first and second ports opening into said housing;
• a flow regulator constructed as a single piece from an elastomeric material and including a substantially cylindrical main body having a central longitudinal axis, said main body defining a flow path through said valve assembly;
• a pair of substantially planar inner walls arranged in converging relationship and extending through the interior of said main body from an inlet end adjacent to said first port to an outlet end adjacent to said second port where said inner walls are disposed adjacent to each other to define a normally closed slit therebetween which intersects said axis, said inner walls being interconnected along the length of said main body by side wall portions of said main body;
• a pair of substantially planar outer walls disposed approximately parallel to said inner walls and extending in diverging relationship toward said inlet end from a point adjacent to said slit to define with said inner walls a pair of lips converging from said inlet to said outlet end;
• a pair of connecting walls having concave surfaces on either side of said slit and extending radially inwardly from said substantially cylindrical main body to intersect said lips and form a pivot portion for each of said lips to pivot away from each other to allow flow in said first direction and wherein said connecting walls and said lips define a pair of cavities within said main body on either side of said slit;
• said concave surfaces and said intersection of said connecting walls with said lips being located along a locus of points which are substantially equidistant from a predetermined center of curvature;
• a substantially circular flange extending from said main body adjacent to said inlet end for forming a seal between said housing and said regulator such that flow in said first direction is from said inlet port, through said inlet end, through said slit and to said out-et end;
• and
• a pair of ribs located on diametrically opposed sides of said main body and extending parallel to said axis in a plane containing said axis and oriented perpendicular to said slit, said ribs engaging said substantially cylindrical interior surface of said housing such that said main body is biased inwardly and said lips are caused to be pressed inwardly to close said slit whereby the pressure required to initiate flow in said first direction may be precisely controlled.