Pressure actuated flow control valve
A pressure actuated flow control valve for an infusion catheter permits gravity flow of a liquid through the catheter and into a patient while resisting back flow of blood from the patient and into the catheter. The valve has a hemispherical body with an outstanding circumferential flange and a normally closed, diametric slit. The slit is longer on the convex outer surface than on the concave inner surface. Dome thickness diminishes in the area adjacent the slit, reducing total apical deflection upon collapse of the slit toward the concave surface. An inner orthogonal rib biases the slit closed. Upon application of a predetermined pressure, the slit opens toward the concave surface to permit forward fluid flow. At lower pressures, the slit closes to check fluid flow. Greater reverse pressure is required to collapse the slit toward the concave surface to permit reverse fluid flow.
1. A pressure-actuated valve component for use in IV therapy to control fluid flow through a catheter in opposite infusion and aspiration directions, said valve component comprising:
a housing including spaced apart intravenous fluid ports and being operable to be fluidly coupled to the catheter, with a fluid passageway extending between the ports to present a passageway axis; and
a valve body being disposed within the fluid passageway and including a flexible dome-shaped wall that presents a convex surface and an opposite concave surface, with the convex surface facing the infusion direction and the concave surface facing the aspiration direction,
wherein said valve body presents a central axis extending along a generally longitudinal plane through an apex of the dome-shaped wall,
said dome-shaped wall including a slit extending between the concave and convex surfaces,
said valve body including a rib projecting from the concave surface, such that the rib intersects the slit generally perpendicularly,
said slit having first and second ends each terminating at an end wall having a thickness and sidewalls extending circumferentially about said concave and convex surfaces of the wall of said valve, said sidewalls each having a circumferential and axial length,
wherein when said slit is at a rest or neutral state, said first and seconds ends are each non-parallel and non-perpendicular to the passageway axis and said sidewalls are in contact with each other at a majority of points along their respective circumferential and axial lengths,
said slit intersecting the rib and extending along the dome-shaped wall radially outwardly from the rib relative to the passageway axis so that the slit termination ends are spaced from the rib.
2. The pressure-actuated valve component as claimed in claim 1 ,
said slit intersecting said convex surface to form a convex arc having a convex arc length,
said slit intersecting said concave surface to form a concave arc having a concave arc length,
said convex arc length being greater than said concave arc length.
3. The pressure-actuated valve component as claimed in claim 2 , said convex and concave arcs subtending a common angle.
4. The pressure-actuated valve component as claimed in claim 1 , wherein said rib is of an approximately rectangular overall configuration with respect to said concave surface of said wall.
5. The pressure-actuated valve component as claimed in claim 1 , wherein said rib is of an approximately hemi-cylindrical overall configuration with respect to said concave surface of said wall.
6. The pressure-actuated valve component as claimed in claim 1 , wherein a shape of the rib with respect to said concave surface of said wall is selected from the group consisting of: oblong, elliptical, and quadrilateral.
7. The pressure-actuated valve component as claimed in claim 1 , wherein said rib includes a pair of ends convergent with the concave surface of the dome-shaped wall.
8. The pressure-actuated valve component as claimed in claim 7 , wherein said rib has a depth that diminishes as the ends are approached.
9. The pressure-actuated valve component as claimed in claim 8 , wherein said rib further includes a pair of sides, and said depth of the rib diminishes as the sides are approached.
10. The pressure-actuated valve component as claimed in claim 8 , wherein said passageway axis is coplanar with said central axis.
11. The pressure-actuated valve component as claimed in claim 1 , wherein said end wall of said slit has an uppermost edge and a lowermost edge.
12. The pressure-actuated valve component as claimed in claim 11 wherein said uppermost edge of each said end wall of said slit is defined by said convex surface of said dome-shaped wall, and said lowermost edge of each said end wall of said slit is defined by said concave surface of said dome-shaped wall.