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.